Computer problem

So I've been using my granny's comp and 2 days ago cause of potential thunder I shut it off, took the battery charger out etc. So a day later I logged into the computer once again but it was like starting the computer for the very first time. All of the files and folders on the desktop had disappeared and when I started Firefox it asked if I wanted to import files from IE. Like first time use ever. I thought: wtf?. The user (on this lap top) is called "Mari Tuulik" so I checked the C/Documents and Settings, I found "mari2" under that and checked the desktop from there and all files were there that used to be on the desktop. I copy-pasted the files back to the desktop but every time you shut down the computer and start it again it will do the same thing. Clear desktop and start the computer like it was the 1st time start. My google searches didn't get me anywhere.
Would really appreciate if smone could help me fix this as my grandmother doesn't even know what a "desktop" is so she could never find the files that are missing etc. Quick help needed as I'm leaving on Friday.
This computer is a Windows XP Home Edition Version 2002 Service Pack 2 btw.

THANK YOU!!!!!

1. Check for virus (probably wont have a virus cos your not a retard)
2. System Restore
3. Backup data, reformat, re-insert data

Possibly your HDD is corrupt. For those types of things its best just to start fresh and format.

If you have no XP disc ask gangplank~yohoho

SX wrote:1. Check for virus (probably wont have a virus cos your not a retard)
2. System Restore
3. Backup data, reformat, re-insert data

Possibly your HDD is corrupt. For those types of things its best just to start fresh and format.

If you have no XP disc ask gangplank~yohoho

Thanks for the info, will try.

EDIT: It seems to have worked. Tho now my granny's slow internet is back cause it restored to the point where all the crap that I deleted is back QQ.