In Windows XP, there are many things that can cause this behavior in a PC. Listed below, are only the most common reasons:
1. Hard Drive is nearing its capacity:
Try removing programs that are no longer needed to free up some space. Be sure to use the programs uninstall tool (if available). If the program does not have an uninstall tool, then remove the program using Add/Remove Programs in your Control Panel. Also, use the Disk Cleanup tool (start>> all programs>> accessories>> disk cleanup) to free-up additional space.
2. Your files could be excessively fragmented:
Try using the Disk Defragmenter tool (start>>all programs>>accessories>>disk defragmenter) to restore the fragmented files to their proper location.
3. Too many Icons on your Desktop:
Excessive desktop icons will make your computer run slow. Try removing the icons (right click the icon and select delete) that you rarely use. Removing an icon from your desktop is only removing the "shortcut" to the program, not the program itself.
4. Too many programs running at Windows startup:
As you continue to download programs, all of these programs startup and run in the background. To stop these programs from running:
1. Go to Start>> Run. Type in: msconfig [Enter] or click OK.
2. Click the Startup tab.
3. All of the programs listed in this menu that have a checkmark are the programs that are currently running. Deselect (by clicking in the checkbox) the ones that you do not want to run any longer. Once you have done this, click OK.
4. Exit the Microsoft Configuration Utility.
5. You will be asked to restart your computer. Go ahead with the restart. Depending on how many programs that you've stopped from running, you could see very positive results in your computers performance.
5. Spyware Installed on Your System
Many web sites on the Internet install "spyware" on your computer so that it can actually "spy" on you. As you surf the web, more and more spyware gets installed. This will eventually begin to slow your computer very noticeably. Therefore, it is important to perform frequent anti-spyware scans with capable software to remove these unwanted parasites. A couple of programs I highly recommend are:
Spybot Search and Destroy