Not every movie file on the Internet has the same file type. Windows Media files are different than QuickTime movies, which are not the same as Real media files. Each format has specific uses and run through specific programs. Here are some of the most common movie file types you will find on the Internet.

Windows Media File

Windows Media video files (or .wmv) are one of the most popular movie file types on the Internet. They are played in the standard Windows Media Player that comes with all Windows computers.

QuickTime Movie

The QuickTime movie format (or .mov) is Apples equivalent to Windows Media Video files. It is very popular because this proprietary video format can be played on both Mac and Windows computers. .mov files are played by apples QuickTime player.

Real Media file

Real media files (or .rm) are files that can be completely downloaded before playing, or can be streamed directly from the Internet. These files can contain audio data, video data, or both. Real media files are
played on the Realnetwork’s Real Player.

MPEG

Moving Pictures Expert Group (or .mpg) files contain compressed audio and video data. MPEG files can be played on either QuickTime or Windows Media Player.

DIVX

DIVx files are high quality compressed movie files. It allows videos to be a lot smaller data-wise while still delivering crystal clear video. There are quite a few different programs that will play these files, but
DIVx does offer a downloadable program that will play these files.

SWF

SWF files are animation files that are created by Adobe Flash. They can contain audio and visual imagery, but instead of movies, the visual components are usually vector images. SWF files are vey popular in web
design and advertising applications. Any web browser with the downloadable flash player plugin can view these files.

What if you are trying to play a video file that is not listed above?

If you have a video file that you would like to play, but is not in one of the above formats, you are going to have to do some extra research to find the correct player or codec. If you type the file extension into
almost any search engine, many results will pop up and give you information on the necessary software needed to execute your given file type.

Database files are used to store different information about what files or information are you using on your computer. Most of them are hidden files, so you do not even see them when you browse through your directories with Windows Explorer, because they are hidden and not showed by Windows by default. You can change these settings in Windows Explorer under Tools – Folder options – View – Show hidden files and folders. Now you can see all the hidden files and with that all the database files. The most common database files that are going to be described in this article are the .db

The .db files, are also called Paradox database file or Progress database file. These files are used to store information, that the system is going to use later and it could acquire it later, but it is faster if the information is stored in it. The most common .db file is thumbs.db, a file where the windows store information about the pictures that are in each folder. As said, the information can be gathered at any time, and that means that you can delete this file if you wish. But it will be later created again, when you access the pictures that you have in a folder.

DBX files are database files, that are used to store information from different programs. One of them that is often used by regular users are the Outlook Express database files. All the emails that you see in your Outlook Express are stored in these files, based on the folders where you have the emails stored. If you would like to delete the emails, or store them to use them on another computer, you use these files. The DBX database are connected with with DBT database files. The DBT files are temporary copies of the DBX files, a way of security, if something goes wrong with the original files you can use the DBT files to restore the information.

Here is a list of other database file extensions:

• .ABD – AmBiz Bonus Calculator data fileAdventure Builder database
• .APX – Appexpert database file (Borland C++ 4.5)
• .BDE – Borland Database Engine
• .BSC – Compressed Apple II file archive created by BINSCIIDatabase (Source Browser)Pwbrmake object file (MS Fortran)
• .BTR – Btrieve Database file; MS Frontpage-related file
• .CDB – Card database (CardScan)Main database (TCU Turbo C Utilities)
• .CIX – Database index (TCU Turbo C Utilities) 
• .CRP – Encrypted database (dBASE IV)
• .CVT – Backup file for CONVERTed database file (dBASE IV)
• .DB – Configuration (dBASE IV – dBFast) Database (Paradox – Smartware)
• .DB2 – Database (dBASE II)
• .DB3 – Database (dBASE III)
• .DBB – ANSYS Database BackupMopheus music file
• .DBF – Database file (dBASE III/IV – FoxPro – dBFast – DataBoss)Oracle 8.x Tablespace File
• .DBK – Database backup (dBASE IV)
• .DBS – Database in SQL Windows formatDatafile (PRODAS)Printer description file (Word – Works)
• .DBX – DatabaseDataBeam ImageMS Visual Foxpro Table
• .DIF – Database (VisiCalc)Output from Diff command – script for Patch commandText file (Data Interchange Format)
• .DSD – Database (DataShaper)
• .DTF – Database file (PFS – Q&A)
• .DWG – Drawing (Drafix)Drawing database (AutoCAD)
• .EDB – MS Exchange Database ROOTS3 geneological data
• .FW – Database (FrameWork)
• .FW2 – Database (Framework II)
• .FW3 – Database (Framework III)
• .GDB – Interbase Database Group Mail file
• .HIS – Insight II Dynamics Trajectory History fileSpy-CD CD Search Database file
• .IOB – 3d graphics database in TDDD format
• .IPD – InstallPROG 6 EDBS Install Database
• .MB – Memo field values for database (Paradox)
• .MDB – Database (MS Access)
• .MDF – Accelio Capture Classic (JetForm) FillerI-deas Master Drafting Machine Data file Menu Definition file MS-SQL Master Database file
• .MPD – MS Project database file
• .MVB – DatabaseMS Multimedia viewer file
• .NDB – Network database (Intellicom – Compex)
• .NG – Online documentation database (Norton Guide)
• .NSF – Lotus Notes / Domino database
• .PFS – Database (PFS:FILE) – text file (PFS:Write)
• .PHO – Phone database (Metz Phone for Windows)
• .PQA – Palm Query Application File (database for wireless access)
• .PX – Primary database index (Paradox)
• .QAD – QuickArt database
• .RDB – TrueVector Rules database, ZoneAlarm Rules database
• .RPD – Database (RapidFile), RosaPro file, RPV Printing System file
• .TDB – Database (TACT)
• .THM – Microsoft Clipart Gallery database, Serif DrawPlus Theme
• .UCS – Universal Classification Standard Database file
• .WDB – Database (MS Works)
• .ZBD – Canon ZoomBrowser Database file
• .ZTD – Ziff Davis Media text database

If you would like to change the default program, that starts when you double click a file, you need to change the file associations.

The first step is to make Windows Explorer show you the extensions of files. The default setting in Windows is not showing the extensions, so you need to change that. Open the Windows explorer and click the "Tools" menu and "Folder options". In the "View" tab band scroll down until you see the "Hide extensions for known file types". This option needs to be unclicked (no tick there). Now, after you click ok, you will be able to see the extensions for all the files.

Now you need to find a file that has the extension that you would like to change the association for. Right click on any file with that extension and choose the "Open with" option. If you see a warning window, then click "open with" again. A window will open with a list of all available programs. Optionally you will see a window saying "Windows cannot open this file". If this happens, click "Select the program from the list" and OK.

Now you will see a list of programs, and you have to choose witch program you would like to use to open files with the selected extension. After you click ok, all the files that have the selected extension will always open with the chosen program.

Be careful while using this procedure, because most of the files have the appropriate default program selected, and if you change it, your system can have serious problems, so use this option only if you are really sure that you do know, what you are doing.

Renaming a batch of files can be done using a program that is specialised for that or you can just use a short command in DOS mode of your Windows. The code is not problematic, and you will be able to use it even if you are not familiar with the DOS environment.

You can get into the DOS command prompt if you go to Start -> Run. Now you need to run the "cmd" program. So just type cmd and click OK. A new window will open, that will show you in what directory you are in. You need to navigate to the directory where you have the files that you would like to rename. Use the "cd.." and "cd target-directory" commands. "cd.." will get you to a directory lower, and "cd target-directory" will get you one directory up, into the target-directory that you specify. You can always go only one directory up, so if you would like to go to c:\program files\windows, you need to do "cd program files" and then "cd windows".

Now that you are in the target directory, use the command "ren *.txt *.doc". "Ren" gives the computer the command to rename files. The second part of the command (*.txt) tells the shell to take all the files with the extension .txt and the third part (*.doc) tells it to rename all the files into the .doc extension.

If you do not want to type so much, you can use one of the many programs, that are free to use and will do the job for you. You can use, for instance the "EF Multi file renamer 1.00", free software that can rename multiple files, a whole directory and its sub directories, if you wish to do so. There are of course other programs out there, a lot of them have other functions, but you will need to pay for them, if you would like to use them.
If you are renaming files on a regular basis, then you maybe should buy one of the programs, but if you just do it a couple of times a year, then just use the DOS command, as described above. It is the old school style, but just because of that it is a reliable way to get the job done.

It is a temporary file stored on the hard drive which contains information or data that couldn’t be loaded into the PC’s RAM memory. It is also known as a pagefile or virtual memory extension and it is used whenever the RAM’s capacity is not enough. In case the computer’s hard drive is too small and the operating system can not increase the swap file’s capacity, the computer might run slower. The location of the swap file using the latest operating systems is in the root of the partition on which the system is installed (ex.: C:\pagefile.sys).

The Windows and Unix operating systems are usually using a default swap file of a certain size managed automatically by the system or it can be configured by the user or administrator. The swap file is being cleared out whenever the PC is being shut down and it is recreated by the operating system when the computer is started again.

How to set the swap file or virtual memory

First you need to access the System’s Control Panel either by using right click on My Computer’s icon on the Desktop, then Properties or follow the path Start/Settings/Control Panel/System then click on the Performance tab and on the Virtual Memory button.You can select the drive on which the virtual memory will reside and set the minimum and maximum size to be used.

DLL stands for Dynamic Link Library which is a collection of small programs used by executable program (EXE) when running. They are generally (but not always) found in your Windows System directory.

DLL files usually end with one of the following extensions: .dll, .exe, .drv, or .fon.

Why are DLL files useful?

DLL help executables to communicate with the devices, such as printers, or contain source code to do particular functions. Even if the main program is loaded in RAM (random access memory), the DLL file is not, so that the space is saved.

DLL files that support specific device operations are known as device drivers.

For example typing something in a word document and printing that document, only for the second process the printer DLL file is called and now it is loaded into RAM.

Deleting a DLL file it is not such a good idea, because your DLL file might be used by more than one program. If you uninstall a program, and decide to delete the DLL file, this file might be used by another program. So when a program is being launched you will receive an error message that the file .dll is missing. You can recover your lost DLL file or you can search it on the internet because there are many sites that provide you support in getting the DLL file needed.

Each file has an extension usually formed from three characters after the name of the file and a period (ex. filename.txt). Usually the operating system on a computer hides the extensions of the files for security reasons but it can be set to be viewable in case someone wants to see the extensions of the files. The file extension is associated with the program it can be accessed with, it simply tells what application is being used or edited with or what type of system file it is.

A list of common file extensions:

ace     Archive, compressed
amr     Compressed audio
arj      Archive, compressed
asp     ASP script, used on web pages
avi      Audio Video Interleave movie or video
bak     Backup
bat     Batch file (executable)
bmp    Windows Bitmap image
cab     Windows Cabinet Compressed Archive
cdr     CorelDRAW vector image
css     Cascading Style Sheets
dat     Text or binary data file
dbf     Database file
doc     Microsoft Office Word document
exe     Executable file
gif      Graphics interchange file format
htm     Web page – HTML file
html    Hypertext Markup Language – Web page file
ico      Icon file
ini       Text configuration file
iso      CD/DVD ISO binary image file
jar      Compressed archive file package for Java classes and data
jpeg    JPEG image, picture file format
jpg      JPEG bitmap image file format
js       JavaScript file
lnk      Windows Shortcut
mdb    Microsoft Access database
mp3    Compressed audio, music file
mp4    MPEG-4 file format
mpg    MPEG 1 video or movie file format
msi     Microsoft Windows Installer installation package file
pdf     Portable document format: Adobe Acrobat File
php     PHP script, page
png     Portable (Public) Network Graphic
pps     Microsoft PowerPoint Slideshow
psd     Adobe Photoshop graphics
rar      RAR compressed archive – backup file
rss      Really Simple Syndication – RSS file format
rtf      Rich Text Format document
swf     ShockWave Flash, Animated vector format for the Internet
sys     System file
tif       Aldus Tagged Image File Format (TIFF) bitmap image
tmp     Temporary file
txt      Common text file
vxd     Microsoft Windows virtual device driver, 32 bit
wav    WAVe PCM Sound, standard Windows sound format
xls      Microsoft Office Excel spreadsheet
xml     XML document
zip      Compressed ZIP archive file and compressed folder