Hey all. Longtime no post. Got a strange issue and hoping someone can shed some light.

This morning, was playing L4D2 and computer hung, did a hard reset and when it boots up again, goes as far as "Verifying DMI pool data........" hangs there for a few minutes and then pops up "A disc read error occured. Press CRTL ALT DELETE etc"

Computer was fine before this happened. No recent hardware changes. It doesnt get restarted very often tho and had probably been running 24/7 for about 3weeks. So if it was an issue with BSD/MBR I wouldnt of known about it untill then, granted.

I tried restarting several times.
I removed all overclocks and reset the BIOS to defaults.
Cleared CMOS

As I was tired, gave up, turned the thing off and went to bed. Just come back to it now. Turned it on and its booted straight into Windows 7 with no complaints. All I got was the "computer didnt boot properly message" and I just told it to boot normally.

This isnt the first time I've had this problem with hanging at Verifying DMI pool data. Last time a few months ago I ended up formatting, rather than investigating further. Baffles me why it would be unbootable 12hours ago and now it seems theres nothing wrong. chkdsk etc all comes back fine. Surely if MBR was kaput, HDD failed or BIOS/CMOS had had it, it wouldnt suddenly work 12hours later...

Anyone have any ideas? Maybe theres someway to verify or check the MBR for errors, as that was my first thought. Could it be an overheating issue? as was hammering it for about 10hours straight last night?

Thank you.