How to Remove Rootkit Virus from Windows XP

Rootkit is a type of malware. Malware, although technically different than a virus, is just as undesirable for your computer. Rootkit can corrupt your system tools and libraries needed to run Windows programs. They can usually be detected by a signature or heuristics-based anti-virus program. Unless you can discover the specific Rootkit and manually remove it, the only sure-fire way to completely eliminate a Rootkit Virus is to back up all of your important data and reinstall Windows.
Instruction

1. Save all your important files to a separate medium other than your infected computer.
2. Insert your Windows install disk in your CD or DVD drive and power off your system.
3. Turn your computer on. Press any key while your computer begins loading to boot from the CD you inserted. Press "Enter" at the "Welcome to Setup" screen.
4. Read the Licensing Agreement. Press "F8" to state that you accept the terms and wish to continue.
5. Select "Format the partition using the NTFS file system" from the next screen.
6. Give your computer time to completely reformat the hard drive and begin installing Windows. Your computer will restart itself when this process is complete. Windows will now install a fresh copy.
7. Select your language and regional information when prompted.
8. Enter your name and organization on the "Personalize Your Software" page. If you don't have an organization, leave this space blank. Click "Next" to continue.
9. Enter your 25-character Windows XP Product Key, printed on the sleeve of the Windows XP disk you inserted in your computer in Step 2. It may also be on the back or side of your computer itself. Click "Next" to continue.
10. Enter all required information in the screens that follow. Make sure you register with Microsoft when prompted. This is where your product key will be crucial to complete your working copy of Windows XP.
11. Click "Finish" when you reach the "Thank You" page. Your installation of Windows XP is complete and the Rootkit virus has been totally removed

Tips & Warnings
Make sure you have a decent anti-virus program that you keep updated regularly to help prevent future infection.

Never throw away any system disks or their sleeves that come with your computer. You never know when you may have to reinstall, and you'll always want the original product keys.