Windows 7: Windows 7 crashes on startup. Can't restore, repair or repair install

Can we go back and run another start up repair?. Try that.

It's on the first Windows 7 screen - the one with a black background which says "Starting Windows" and has 4 balls of light which turn into the Windows logo. It crashes as soon as the first two balls of light appear and start moving. I think I just noticed a BSOD screen flash up extremely briefly before it restarted.

Edit: ok, I'll try that again.

Have you installed anything new recently?.

Any updates?

Have you got any usb devices pluged into it?
like a printer, or storage device?

If so, disconnect them.

Ok, Startup Repair now says
"Startup Repair cannot repair this computer automatically
Sending more information can help Microsoft create solutions"

The problem details say
"Problem event name: StartupRepairOffline
Problem Signature 01: 6.1.7600.16385
Problem Signature 02: 6.1.7600.16385
Problem Signature 03: unknown
Problem Signature 04: 21200089
Problem Signature 05: AutoFailover
..."

There's more if you'd like me to type it. It was weird; Startup Repair didn't even seem to take any time this time - it ran for maybe 2 seconds and popped up with this error.

Edit: No new updates in a while (I turned auto updating off) and no new USB devices plugged in. Right now only a mouse and keyboard. Come to think of it, my computer was knocked over recently and I might not have started it since then, but I don't know if that matters.

ok. I suggest we now re-run a sfc \scannow from command prompt

Ok, I'm using this code: sfc /scannow /offbootdir=c:\ /offwindir=c:\windows
which I got on these forums (sorry, I'm not very experienced with command prompt).

It's still running; I'll let you know when it's done.

I've just been re-searching the Problem Signatures.

a lot of post are relating them to be Driver related?.

Have you installed, or updated any drivers recently?. Installed any new hardware?.

Are you sure we can not access windows Via safe mode?.

I've definitely tried before, but it was before I posted on here, so I'll try booting it in safe mode again once this sfc /scannow is finished. I haven't installed any new drivers, but I am currently running the hard drive in my other computer (not it's regular one). This hard drive's regular computer is so much slower and louder (it has fans running at 100% until it gets into Windows - so the entire time I'm doing this). I was getting the same problems in the old (regular) computer, but if these are new hardware issues, should I just put it back into the old computer?

Sorry, it completely slipped my mind that this might be an issue.

Edit: The scan just finished and said "Windows Resource Protection did not find any integrity violations"

Edit again: Safe mode still didnt work. It went through a few different lines of writing and then BSODed again.

Edit again again: The line it freezes on ends with "drivers/CLASSPNP.SYS" (not sure what the something was)

I could have done with knowing this at the start.

You can't just take a OS hdd out of one machine and expect it to boot in another, It has all the wrong drivers trying too boot, Hence why it hangs.

You should definetly plug it back in the old machine.

Ah, sorry about that. I figured it wasn't an issue since the same error seemed to be occurring on both computers, so I figured I use the quieter one. I mentioned in the OP that I was using it, but I guess I wasn't clear that I was still using it. Sorry, I'll switch it over now.