Vista won't start

Hi all,

I've just started having boot problems with Vista. I've had no problems in the past, but earlier this evening it would restart itself while loading Vista (the green bar loading stage). I used the Startup Repair option from the Vista install disc, and the log shows it successfully repaired a corrupted system volume (exact wording may have been different). Now it boots as far as loading a black screen and the mouse cursor, but doesn't get to the Aurora (blue-Vista-Windows-logo-loading thing).

I have tried subsequent Startup Repairs, CHKDSKs, Memory Diagnostic checks, all with no errors to report. Unfortunately, I disabled System Restore a while back... Something I now regret doing! At least I know what I'll be doing as soon as I get it running again!

My system is an ASUS M2N-E motherboard, AMD Athlon64 X2 6000+, Corsair 2x1GB XMS2 RAM, Sapphire ATi Radeon 3850... And so on and so forth. I'm running Vista Ultimate 32bit as well.

Thanks in advance!
- Noddy