I suggest she uninstall any unused programs and do a disk cleanup Start > Accessories > System Tools > Disk Cleanup. I use ccleaner but disk cleanup will get rid of some of the junk. She can then start the computer in safe mode by tapping the F8 key as the computer starts up. She will get a screen where she can choose to startup in safe mode. She can then right click on 'My Computer' click on 'Properties' click on the 'Tools' tab and check for errors by clicking 'Check Now' and then defrag by clicking 'Defragment Now'.
This can be done without starting in safe mode but for someone who is new to the process I think this is the easiest way.

The old "scandisk" from Windows 98 is now called Error Check on XP. Several ways to get there, but here's one way:

1) Left click (twice) on My Computer desktop icon
2) Right click the hard disk (usually C)
3) Click Properties
4) Open the Tools tab
5) Choose Error Checking (check now button)
On next boot up, the scan will run. It will take a while depending on the size of the hard drive. Then run the defrag utility.

I have had this computer for almost a year & never done a scan disk..will it also check drive D? I have a large drive & I know it will take forever to scan... guess thats why I haven't done it :(
Dar

Sugar, when you open "My Computer" it should show all your drives. Just right click the one you want to do the scan on. I assume they have to be done separately. My D drive is the recovery partition, so I never scan it because it's never used. Yes, the larger the drive, the longer it takes, so you just might set aside a time when you won't be needing to use your computer to do this task.