Windows Vista won't start (Hardcore)

[Indybird]

Leading up to the problem:
So a while back my friend got a virus from a bad download. We ran a fully updated Anti-Virus and got rid of the Virus and all of its traces. After that his computer ran fine for a day or two. Then all of a sudden and out of nowhere he began getting a lot errors (of which he can't remember the details). He re-ran the anti-virus again but it didn't find anything. He then restarted his computer and here we are now.

The Problem:
The computer POSTs, starts windows, displays the cursor on the blank screen and thats where it stops. It's not frozen as you can move the cursor but it never continues past that point.

Fixes I've tried:
-Starting Windows in Safe Mode: Resulted in the exact same problem
-Run Startup Recovery off of Vista Disc: "Found no problems with startup"
-System Restore: No restoration points
-Ran chkdsk utility off of a Windows Installation on another HDD: found and fixed "errors", but didn't fix the problem

I don't know where to go from here aside from re-installing windows. All of his files are accessable and we can back them up no problem, but I would like to try and fix Windows if it is at all possible instead of just re-installing.

Thanks,
Indybird

[HackSore]

It would seem that a reinstall of windows would be the best and safest bet.
Have you tried doing a repair install? (i havent really used vista much, but xp came with the option to repair install, which was basically a reinstall of windows, but didnt require a format or losing any data, though it warned that data could be lost in some cases.)