If you do have a virus or malware the best thing to do is a clean install of the os.
1. Start your computer from the Windows XP CD-ROM. To do this, insert the Windows XP CD-ROM into your CD drive or DVD drive, and then restart your computer.
2. When you see the "Press any key to boot from CD" message, press any key to start the computer from the Windows XP CD-ROM.
3. At the Welcome to Setup screen, press ENTER to start Windows XP Setup.
4. Read the End-User License Agreement, and then press F8.
5. Follow the instructions on the screen to select and format a partition where you want to install Windows XP.
6. Follow the instructions on the screen to complete Windows XP Setup.
Install your antivirus next. If you don't have one you can get a copy of EArmorLE from Computer Associates with the first year free.
http://www.my-etrust.com/microsoft
After completing the install immediately do all of the online upgrades, including service pack 2.
Then install your programs.
Good Luck Lee