Windows 7 just lost all it's drivers and screwed up settings

Right, I was just about to play on Sims 3, so put the disk in the drive. I caught the power button on my case, and took the disk out before the computer turned off. Thought nothing of it.

Booted it up again, and it's all screwed up. 800x600 resolution, an error message saying that my ATI graphics card wasn't recognised (or something), no keyboard or mouse (I have 2 sets - a wireless and a wired - neither worked), no Aero, no Wi-Fi. The only thing I had was sound (which I use the default Windows drivers for). Then it blue-screened, DRIVER_IRQL...

Rebooted, and the graphics drivers are on default Windows ones now (so 1024x768 and Aero), Wi-Fi card doesn't display at all in Network Adapters, Avast! is throwing up an error about not being able to scan mail/news, and System Restore is showing as turned off, but below it there is an entry that says

(C:\)(Missing)

Which has protection turned on. Err, help?

Not overclocked at all, installed wireless keyboard 2 days ago, no problems since, and I ran Prime95 for 4 hours last night (which I suspect could have caused problems, but seeing as I can't do a system restore, I'm up **** creek without a paddle)

Computer specs are
Athlon II X2 250 @ 3Ghz (stock)
Stock cooler
Asus M4A77TD Pro
Sapphire HD 4670 512MB GDDR3
2GB DDR3-1333 Corsair Value RAM
500GB Samsung SpinPoint F3
LiteOn iHAS124-19
7 Ultimate 32-bit.

So, err, I think I need to do a Jewish Bear (backup, format, reinstall), but I want to know what the hell caused this first...

+REP for helpful answers, -REP for being a jerk.

Perhaps it had something to do with DirectX?

Just a thought.

I'm gonna try and reinstall the latest Catalyst and Asus Wi-Fi drivers, but I'm quite worried now... especially as I can't find my Windows disk....

had sims started to load up when it went off? if yes it could of been loading files mabey? and they corrupted because they were unable to finish, i have a windows 7 disk around here somewere, if i find it PM me if you dont find yours and ill copy it and post it to you if you like?

nah, when i caught the button, I'd only just pressed the eject button to close the drive. It nearly went into the drive, before it ejected, and I took it out just before I got to the Logging Off screen.

2fast2kwl: thanks for your kind offer, I'd really appreciate it if you are able to find your disk.

ill start looking around now, are 32bit or 64bit?

32-bit at the moment, but I might be switching to 64-bit soon. Either will do, If it's 64-bit, i'll get a code.

Ill keep looking then, i have both disks, but there OEM if thats ok?

OEM will work as long as I can obtain a code, so that'll be fine :)

IRQL_NOT_LESS_OR_EQUAL is either corrupt drivers or a RAM problem (i.e. corrupt, mobo fault etc)