Sounds like the virus might have wiped out your MBR. If you have your XP install disk, put it in the cd/dvd and go to the recovery console
1. First, restart your computer with the Windows XP setup disk in the CD drive. If you don't have your original disk, borrow one or download a ISO image from a torrent site.
2. When prompted, boot from the CD drive by pressing any key. If Windows loads automatically, you will first have to enter the BIOS setup and change the order of the boot devices to start with the CD drive.
3. Once the setup loads, you will see the option to press R to repair a Windows installation.
4. Once the Recovery Console loads up, you will have to type in a number that corresponds to your Windows installation. This is normally just 1. Press Enter and then type in the Administrator password.
5. Now at the prompt, type in fixmbr. Your damaged MBR will now be replaced with a new master boot record and your computer should now be able to boot properly. Note that you may also want to run the fixboot command to repair the boot sector with a new one.
Also, make sure you only use these commands on a system with one operating system installed. If you have more than one operating system installed, fixmbr and fixboot could mess up everything.
You can also download Hiren's boot CD and burn a live cd that will fix most anything for free. If you have problems an need more help you can email me at: [email protected]
Just put MBR in the subject field