Is this another virus?

[Radical Edward]

I have a bit of doubt, but the fact is that I had a virus at Halloween that looked EXACTLY like this. Here's the story:

I was using Windows XP today because linux won't run my EuroTalk software. Nothing remarkable happened all afternoon except that a cd-rom drive that hasn't opened in weeks opened and was useful. I figured I'd just forgotten to plug it in back when I was rebuilding the computer, but since I did plug in the other one, I haven't bothered to open the case and fix it yet. So... I guess it had some other problem, because I didn't do anything to it, it just randomly worked.

Anyway, back to the plot. I was planning to do a backup tonight, and I habitually do a scandisk and a defrag of C: before I back it up, because that's how they taught me to do it and I am a creature of habit. So, I set up a scan for C: and rebooted the computer. It scanned and scanned, and then said it had made changes to the filesystem, and rebooted. On reboot, it went right back to scandisk. Er, chkdsk, whatever it is now. I tried to press any key to cancel, but it scanned anyway. Great time for my keyboard batteries to die, right? Nope, the batteries are fine. I restarted again, hit DEL and looked through BIOS to make sure the keyboard was properly functioning and rebooted again. It still went back to scandisk. No pressing any key would cancel it, no escaping or CTRL+ALT+DEL would reboot it. I had to hit the reset switch on the box. I can't get to a Safe Mode or a boot menu (just the one where I can pick Fedora or XP). I haven't let it scan a second time through because if it is a virus, it's likely to be fucking my shit up rather than actually scanning. What bugs me is that the keyboard is non-functional when I get to the blue screen. A normal scandisk would let me cancel.

So, if it's a virus, how might I rid myself of it without actually getting into windows or having to format the drive? And if it isn't, and is just a Windows malfunction (and TBH that wouldn't surprise me a-tall) how do I go about fixing it? Any help would be hot.