[Inquisitor]

If your computer was on a network, I would suggest getting all your files off the hard drive before you try anything drastic.

Another safer option would be to get hold of a boot disc. You can do a virus scan from outside of Windows. Do a search for Hiren's boot disc. That's pretty good.

If you absolutely have to keep the data on the hard drive and cannot access it, then you could try the following. But I warn you, it's not for the faint hearted.

Get a clone disc program such as Acronis True Image or Norton Ghost. Clone your hard drive. Save the image to a DVD Disc (don't worry, all this can be done from outside of Windows).

Reinstall Windows. What the hell, why not install Windows Vista with SP1? (If your system can handle it). Once everything is working, make sure you have a separate partition on your hard drive to restore the clone image to. If you don't have enough space, buy another hard drive (internal or external, it doesn't really matter so long as you have USB 2).

After you restore the image, you can access all your files.

Note: if you are forced to buy a new hard drive due to lack of space, then you could install Windows on there and then connect your old hard drive and access files as normal.

The cheapest and easiest option would be to take out your hard drive, hook it up to another computer (your own or a friend's) and backup the files from there. Then simpy reinstall Windows.

But seriously, cloning your hard drive and keeping a back up copy is always a sensible thing to do.