Click start then run, type sfc /scannow then press enter, you need the XP CD and get a blue progress bar, when the bar goes, reboot.
You can check for any improvement now, and then after each step until you have run through them all, if necessary
When it has loaded to the desktop, click start then run, type chkdsk /f /r
then press enter, type Y to confirm for next boot, press enter then reboot.
This will take an hour, it will appear to load normally then either the monitor will show progress or the screen will go blank, do not disturb this.
When it gets to the desktop, the system files and the hard drive will be as they shouldClick start, all programmes, accessories, system tools to run disc clean up, click more options then clean up restore points, click confirm, click OK. Then from system tools, run disc defragmenter.Click start then run, type prefetch then press enter, click edit then select all, right click any file then click delete, confirm delete, then rebootThe Next steps are optionalGet the trial of Tune Up 2006 hereTune Up 2006 TrialRun disc clean up then registry clean up then click optimize to run reg defrag, which needs a reboot
After the reboot, click optimize then system optimizer to optimize the computer, select computer with an internet connection from the drop down menu, this also requires a reboot
After the reboot, click optimize then system optimizer to accelerate downloads, select the speed just above your actual connection speed, this requires a reboot
After the reboot, click optimize then system optimizer to run system advisor