Hackers are always try to get into computers of other persons. It can be something as simple as phising confidential information ( like bank account numbers or credit card ) to complex hacking routines that use your computer as a repository for illegal content (like movies or music with copyright).

Unfortunately there is no magic or any software to prevent hackers directly   and it will never exist in future. It doesn’t matter how much money or resources we invest to design the perfect system, somebody will always try to find the way to crack it. Even the biggest government agencies like NASA, CIA and NSA have been victims of hackers but they can’t do anything and the same thing happens in the private sector with companies like Citigroup or Wal-Mart and many more.

The first thing we have to take care that in computer hacking prevention is to assure yourself that all your software is up to date, especially our operating system and our web browser.  Because they are the two things that hackers will try to attack first if they want to get into your computer.

The second thing that we need to do is to install a firewall. Internet firewall hacker protection has become so necessary that Microsoft now ships it for free as part of their Windows XP operating system to protect our pc.

At the end, there should be the anti-spyware program. As if viruses were not enough, companies from around the world decided to create programs that could pick up data from your computer in order to acquire information for their databases. It may not be as dangerous as a virus, but it is an intrusion to your privacy. Wipe them out with this piece of software.

Keyboard Activity Monitoring Tool is a hidden inspection utility that keeps track of all activities performed on your system in your absence. keylogger will let you monitor whatever work is done by the people in the background.

Key logger will records every keystroke make by the user in every application and save it to a text document/files. All major anti-keylogger or spy tools can’t be major by any anti-virus softwares. It is easy to use key catcher software helps you to watch your co-workers  are doing online, students are doing at lab,school and at home. So by using this software you can easily customize keyboard activity in the manner you want.

Features of keylogger software:

• Very easy to use
• Can work in invisible/hidden mode
• Invisible in window explorer
• Small size and low system requirements
• Capable of removing programme shortcuts from start menu.
• Capable of removing itself from uninstall list.

A hidden directory or hidden file on a computer is a directory (folder) or file which a user can’t see by default. The Hidden directories/files are  most often serve to hide important operating system-related files and user preferences.

Showing hidden files  is not a big task—for example, If we want  to delete everything from a floppy disk and the disk properties still indicate 100K of disk space which is  used by hidden files.

To see hidden files:

Note :To access Windows Explorer, click Start, point to All Programs, and then click Windows Explorer.

Most of the files that you delete are send to the Recycling bin. This helps you to recover files that you delete by mistake. On the other hand there are different files that are not send to the Recycling bin but are instantly deleted, so that you can not recover them from the Recycle bin.

If you delete a program through the “Add or remove programs” option in the Control panel or just uninstall a program, then all the files that will be deleted won't be send to the Recycling bin.

When you delete files in the MS-DOS prompt then they are instantly deleted and not copied to the recycling bin because the recycling bin is not a MS-DOS program.

You also won't be able to recover files from the Recycling bin if you delete them from a floppy disk or a USB key or any other removable drive. The Recycling bin is connected only to the hard drives on your computer and so does not store any of the files that you delete from other drives, so you need to be really sure when you delete files from such drives.The same goes for files that you delete from a network drive, so if you work on a home network take caution when you delete files.

The last kind of files that are not send to the Recycling bin are really big files. The Recycling bin has a set size. This means that the recycling bin will not get bigger than the allocated disk space. If the file is bigger than the set size of the recycling bin then Windows will alert you that the file will be instantly deleted and you will not be able to recover it. You can change the allocated disk size for the recycling bin if you right click on the recycling bin and click on “properties”. Now you can set the size of the bin as a percentage of the size of your disk(s). The default percentage is 10%, but if you often delete files that are bigger than this and you would like them to be send to the recycling bin, then you should change the size, but do not make it too big, because you will loose the empty space on your disk.

So, you have deleted a file that you would still need? It is not such a big problem as it looks like because there are several ways to recover your deleted file. Before we tell you how, let us tell you why you can do this.

The deleting process that is used by Windows and most other operating systems is not really a deleting process. The file is not deleted from the disk, but the computer is just told, that the file is not there any more. It is just like if you would delete an entry from your DVD database. You would not be able to find it any more but the DVD would still be just where it was. Until you would change it for something else. And the same goes for the computer. If the file was not overwritten, then you can still recover it.

But before you do that, you should go and check your Recycle Bin. Most of the files, that you delete are just copied into the Recycle Bin. Until you do not empty your Recycle Bin, you can always recover the file. Just open the Recycle Bin (you will find it on the desktop or in your Windows explorer), scroll down to the file that you would like to recover and right click on it. Now click “recover” and the file will appear in the directory where it was located before you have deleted it.

If your file is not in the Recycle Bin any more, then you will need a file recovery software, that will look for your file. There are several programs out there that you can download and use for file recovery. Some of them are “PC Inspector File Recover”, “Restoration”, “Undelete Plus” or “FreeUndelete”. Use any of this software and if the file that you would like to recover has not been overwritten, they will recover it for you.

If none of this helps, you can take your computer to a file recovery company near you. They use sophisticated programs that can recover files that you can not.

Private information, private photos, or just a present for your loved one in a word files, all these are files, that you need to protect on your computer, so that other people can not access them, or even see them.

The first problem here is that the operating system Windows XP does not have encryption software, when you install it. The best way to do the job is to get third party software that you can use to hide and encrypt your files and folders. There are many different programs that you can use, such as WinCry, a free program, or a commercial version, called Folder Guard. These programs will give you the biggest security that you can expect from a program on Windows XP.

You need to know, that there is no 100% security, and if someone really wants to get to the file, he will. But, for the normal user, you can use any of these programs.

There are ways, how you can hide your files and folders, using just Windows XP. You need to choose a folder that is connected to your account that means that it is located in the C:\documents and settings\your-name\ folder. If that is not the case, then you won't be able to use this option, and you will need to download one of the mentioned programs. But if you would like to protect a folder within the \your-name\ folder, then you navigate to the folder in Windows explorer and right click on it. Choose properties and the "Sharing" tab. Now here you can choose the "make this folder private" option. If you tick this box, this means, that the folder is only accessible to you, when you are log into your windows account. So if your son, for example, uses another account to log into Windows, then he won't be able to see the folder. But if someone uses the computer while you are logged in, then he or she will be able to see the file.

So Windows XP have only limited ways to protect your files and folders. If this is not enough for you, then download a program, and use it. It will give you a much better protection.

Association of a file with a program can be changed when a new application or software is being installed on a system that’s why it is helpful to have a step by step guide about how to fix this problem whenever it occurs.

Here are the steps you should follow whenever want to associate a file with a particular program:

1.    Open Windows Explorer and the folder under which your file is located.

2.    Right click on your file, go to Open With and in case you will find the desired Program in the navigation, then click on it otherwise you will have the option to Choose Program… in the bottom of the navigation.

3.    After Choose Program… a window will open in which you will find two categories of application lists you can choose from: Recommended Programs and Other Programs. These two lists contain the most common programs used on your computer.

4.    In case you still can not find the program you want your file to be associated with, there is a Browse button which helps you navigate to the location and executable file of the application you want your file to be associated with.

5.    In order not to repeat this steps all the time, you can select the following option: “Always use the selected program to open this kind of file” regardless of the location of such files, they will always be opened with the newly selected and associated program.

In case the program is missing from your PC, Windows offers the option to look for an appropriate program on the Web.

How to add, modify or delete a file type:

For this you can use the Tools menu in Windows Explorer, then Folder Options and selecting the File Types tab in the small window. Here all registered file types will be listed and you can create new file extension by hitting the New button. To remove or delete a file type all you have to do is to select from the list and hit the Delete button. Modifying file type properties, you will have to use the Advanced button positioned in the bottom section of this window. You can change the icon of the file extension as well as edit the actions of the file type.

Compression is a process of transforming more files in only one file, smaller than in their original form by using a compression algorithm. The compressed files help us to download copy or share faster and easier the specific files on a computer. Also, once the files are compressed, you can store more data on a removable media.

Extensions:

The most used are: .ZIP, .RAR, .ARJ, .TAR, .GZ and .TGZ. Besides these you can also find:

.ace      .c01      .gz      .sit          .uu

.ain       .c02      .hqx     .sitx        .uue

.alz       .car       .iso      .tar.gz     .z    

.ar        .cbz       .lha     .tbz         .zip    

.arc       .cpt      .lzh      .tbz2       .zoo 

.ari        .dar      .mim     .tgz        .000

.arj        .dd       .mme                 .7z 

.as        .deb      .pak 

.bh        .dgc      .pf 

.bhx       .dist      .rar 

.b64       .ecs      .sea 

.btoa      .efv  

.bz 

To view the compressed files, you need a compatible decompression program that can read these codes and convert the data back to its original form.

For Windows XP, or any other later operating systems, users can compress files simply selecting the file, Right click on it then Send to / Compressed folder, as these operating systems include the compression option. File will be saved with a .zip extension. For the other windows versions, users must download and install this utility.Concerning the Linux or Unix operating systems, these have both a command that can compress and uncompress the files.

We can distinguish two types of compression methods: 

Lossy compression
Loosy compression method is when after a compression and a decompression, the files resulted loses from its quality, but it is still useful. The multimedia data like audio and video are the most exposed to the lossy compression. If the same file is compressed and decompressed repeatedly, the file will progressively loose quality and after a time might be useless.

Lossless data compression
Lossless data compression is the opposite of lossy compression. This method is based on algorithms that reconstruct the original data after compression. Some image file formats like .png and .gif use only lossless data compression.

A temporary file is automatically being created to store information temporarily when a new file is being created or accessed for modifying its content. The temporary file, also known as a foo file it gets automatically deleted when the program of the file is shut down. In case the temp file(s) are not deleted after the program has been closed, it is safe to delete them manually as they are not needed any more.

Temporary files are very useful as they will keep the information even if there is a sudden halt of the PC and it makes possible to recover data. It is advisable to delete temporary files as they might accumulate in time and slow down your PC’s performance. There can be many types of temporary files like internet files, offline web pages, downloaded program files and others.

New operating systems have a built in utility for cleaning up temporary files automatically. This utility is called Disk Cleanup Wizard and can be accessed by clicking on Start / Programs / Accessories / System Tools / Disk Cleanup. A shorter and quicker way to run this application is to click on Start then Run and type the following command: cleanmgr.

You can select which partition to be cleaned and usually the Disk Cleanup utility will also erase the content of the Recycle Bin or Trash.