Is it a virus?
Could be, especially seeing how this machine has not been fully updated. After trying acklan's suggestion see if you can use system restore to a date as far back as possible. More info on this can be found HERE
If you can get this computer to boot I would recommend following the Preparation Guide to posting a High Jack This log. You may not need to actually post a log, however. By following these instructions you will use virus scanners, and if they find anything, thn you may want to post a HJT log as instructed in the Preparation Guide to insure you have cleaned this computer properly.
Of course you could just decide to scrub this computer and reinstall Windows. That would take care of this issue also. You should run Killdisk to delete everything including any infections. This is a free progam and can be downloaded HERE
. Put the program on a floppy disk or a CD.
Then run a DOS disk, such as a Windows 98 start up disk, when the computer boots to DOS, type "C:" (without the quotes), push ENTER. Then type "fdisk" (without the quotes), push ENTER, then just push ENTER at each selection that you are prompted to make (in other words, just accept all defaults). You can download what you need HERE
Then reboot with your XP CD in the cd drive and reinstall Windows, being sure to choose "Full Format" instead of quick format when prompted.
Be careful about reinstalling your data as it may contain a virus or other malware.
If there is important data to recover first, you could always remove the hard drive and install it in another computer as a 'slave' drive. The working computer should still boot up from the 'good' Master hard drive, and then you will be able to navigate (Start > My Computer
) to the slave drive and recover your data. More info on how to install a second drive can be found HERE
But of course, if you need help with this or any other procedure you can just ask for help here and we can explain it in more detail or refer to somewhere on the web where it will be explained more fully.