As far as I'm concerned backing up your data should be priority number one. Even if you can't run windows long enough on your computer either download a bootable copy of Linux such as knoppix or ubuntu or slave your drive to another computer and copy your documents either to that computer or to an external hard drive. I recommend getting an external hard drive so that you can always keep your data backed up.

Its important at this point to backup because not only could the problem be with system corruption (which could require a reinstall) or hard drive corruption but there could be a number of other hardware problems and it might come down to doing a reinstall just to rule out windows. However it is premature to go a head and reinstall because what if the problem is your hard drive and your installation files are on the hard drive? Either the installation won't complete (which could lead to you being without a system), the drive fails (which it could anyway), or possibly (but not likely) it does complete but perhaps with a corrupted system. If that happened it might therefore look more like hardware failure other than the hard drive.

I don't like the idea of restore partitions because of the fact the a hard drive failure could wipe out the recovery files. Why not just ship out a cheap disk or disks?