How is this even possible (hard drive/windows error)

My computer has been rather dead the past few days, and I’ve managed to isolate the culprit. Not that running chkdsk (which doesn’t find any errors at this point) or doing a system restore does not fix the issue.
I can start Vista in Safe Mode to a different profile than my regular one, or repair console, and it doesn’t find any errors. I can start Vista in normal mode with a different profile than my regular one, but when I start Vista with my regular profile, it loads the Vista default profile, works for a few minutes, then locks my computer completely (can move mouse pointer). When starting with another profile, it works until such a time that a program of any kind tries scanning my regular profile, which will be when the entire computer locks up (can move mouse pointer). What magical powers does this file segment have, really, that it can cause a virus program, for instance, to lock Vista up completely?
I’ve backed up some of my important data, but probably need some more, after which I must decide whether to try to salvage this system, install Windows7, or do a complete factory restore.

Caching on hard drives creates all sorts of weird issues where a system will perform normally for a nominal amount of time, then it needs to access non-cached data and bam - lockup.

Hook the drive to another system, Teracopy your important data first, then run diagnostics on the drive. Maybe Hard Disk Regenerator can patch over the bad sectors, but I’d just replace the drive if SMART tells you it has more than 25 bad sectors.

You wouldn’t happen to have SpinRite available? That’s by far the best tool to diagnose defective hard disks.

I’m running the WD Diagnostic Tool, and it seems to have stalled on the problematic sector. I guess that means the problem is in the hardware?
I’ll still make an attempt with a Windows 7 installation, but I’ll probably end up sending it back under warranty.

No, that just means the WD tool sucks. When my Raptor had a bad sector I ran the WD tool and it just stalled, too. SpinRite correctly identified and marked the bad sector.

I think I’d rather hand it in for free repair/replacement than pay $89, though.

…and it’s out of warranty. Stupid lease-purchase rules :(

Please tell us, you checked your RAM.

Even if it was under warranty, that doesn’t do jack to get your data off the drive, whereas Spinrite (or HDD Regenerator) could fix that bad sector and potentially give you access to your data again.

I have no problem getting the data off my drive, I can do pretty much anything I normally do until the computer tries to access that particular sector.

Ah, that’s good. If the drive has otherwise fine health in its SMART status, then I’d run HDD Regen on it, see if it operates normally after that, then repurpose it as a backup drive. I wouldn’t trust it to hold the primary copy of my files, but a backup drive doesn’t need to be bulletproof.