Windows 7 Boot error

[Bens_Dream]

Hi,

A while ago, when I installed my new HD 6570 as an upgrade from my current GeForce 7100, I rebooted, and it worked fine. Two reboots later, my computer gave a BSOD of PROCESS1_INITIALIZATION_FAILED, with an 0x0000006B error. It did this on every subsequent boot.
I managed to fix this by performing a system restore and by letting system repair run.

On Thursday, however, we had a powercut in the area, and when I rebooted my computer, it gave the same blue screen error. That's fine, I fixed it again with the same process.

However, on the night between Friday and Saturday, Windows 7 auto rebooted to install updates and went into a constant reboot cycle.

I woke up on Saturday morning, and my computer was on the same BSOD. I no longer have the HD 6570 card, so it can't be that that's causing the problem any more.

Since then, I've tried the following:
System restore (All four points)
System repair (Upwards of 30 times)
Chkdsk with a /f switch on all drives
SFC on all drives
Removed my bootcat.cache file to no avail (I've now replaced it)
Tried safe mode, doesn't boot
Tried low resolution
Tried last known good configuration
Tried disabling driver signature enforcement

Things I'm not willing to do (I have 600GB of data that I couldn't risk losing, and I can't afford an external drive at the moment):
Chkdsk with a /r switch
Reinstall Windows, even if it's an "upgrade" install that keeps your data - There's no guarantee that it will work without fail
Backup to an external drive and then format
Anything else that could cause data loss

Could someone possibly assist me and provide me with more ideas in order to fix this? I can access most system .exe files with the exception of things like msconfig and devmgmt, by typing "notepad" into command prompt from the Windows RE and then right click --> opening the file.

I have a Windows 7 install disc that allows me to access the RE.

Thanks in advance,

-Ben.

[Bens_Dream]

Thanks for your input, though for me it's definitely not a disk error. I know there's a corrupt file somewhere but I can't find what it is (Safe mode and boot log shows that it occurs after CLASSPNP.sys). On top of this, I've only had this drive since January, plus I've fixed the exact same error three times in the past, though it's not working this time around.

Edit: When "Disk failure" popped up did you lose all your data? And did this occur after Friday night's Windows Updates?