not im not IT expert, this is extracted.

Over time, Windows XP tends to get clogged up with extra files and programs that can slow down your computer's performance and cause your computer to behave strangely or even stop working altogether. Here's how to keep Windows running smoothly.
Delete Unwanted Files and Programs
Windows Disk Cleanup Utility keeps your hard drive free of unneeded files and programs, frees disk space, and can even speed up PC performance.
Click Start | All Programs | Accessories | System Tools | Disk Cleanup to start the utility.
Select the hard drive you want to clean from the pull-down menu and click OK.
Be patient. It may take a while for Windows to scan the disk (see Figure 1). When done, Windows displays the categories of files it deems suitable for deletion.
Figure 1: Be patient. This box means Windows is analyzing the hard drive.
Click a category to see a description of the selected files to be deleted. If you want to see a list of the individual files in a category, click View Files (see Figure 2).
Figure 2: Pick a category and click View Files to see all the files and folders to be deleted.
Double-check to ensure you're not deleting any important files, especially those in the Recycle Bin (see Figure 3).
Figure 3: Check the files and folders in each category before deleting, especially those in the Recycle Bin.
Click the More Options tab to remove even more files.
When you're ready, click OK to begin the cleanup process.
Delete Unwanted Startup Programs
As you add software to your PC, the number of programs that automatically start with Windows get bigger and bigger. You probably don't need all these programs running all the time; they just eat up memory and increase the chances of a software conflict. To remove the ones you don't want:
Go to Start | Run and type msconfig in the text box shown in Figure 4. This brings up the System Configuration Utility
Figure 4: Type msconfig to start Windows' System Configuration Utility.
Select the Startup tab. You'll see a list of all the programs that automatically start with Windows (see Figure 5). Remove the check in the box next to a program name, and that program won't start with Windows.
Figure 5: Disable any programs that you don't need or don't recognize by removing the check from the adjacent box.
Click the Enable All or Disable All buttons to do just that.
If you're unsure what a particular program does, look under Command for the location of the program file.
Pick the programs you want to disable, or click Enable All or Disable All to manipulate all the programs at once. Remember, you can always start a disabled program manually from the Start | All Programs menu or by finding the program's executable file in Windows Explorer and double-clicking it.
Reboot your computer to compete the process.
Keep Windows Up to Date
Windows XP is a work in progress; Microsoft is constantly issuing updates to fix bugs, security holes, and problems. Updating your Windows files is one of the most effective ways to keep your PC running smoothly and safe from unwanted intruders.
Click Start | Help and Support. Under Pick A Task click Keep Your Computer Up-To-Date With Windows Update.
Windows will scan your PC and offer you two choices. Pick Express Install to install critical updates or Custom Install to install some or all of the available updates (see Figure 6).
Figure 6: Select Express Install for the most important Windows updates.
Windows can automatically download updates and alert you when they're ready to install. To enable this, go to Start | Control Panel | System and select the Automatic Updates tab. Select Download Updates For Me, But Let Me Choose When To Install Them (see Figure 7).
Figure 7: Set your PC to automatically update Windows.
