Asus Rampage Formula, big errors?

[TridenT]

Last night I left my computer on letting it download some files as it played back some podcasts for me while I fell asleep. Well.. to my surprise when I woke up, the computer was on... but unresponsive. My USB Mouse had its lights off and I thought, "Oh f me, not this bs again." To my surprise when I turned on the screen, yes... no screen. It was in its sleep mode because it was getting no signal. I reset my computer and it starts saying, "Checking for CD ROM..." Checking for USB Device...' over and over... it does this. Apparently there was some kind of Bios boot sector block error or something with the version 0.24 or something. I can't remember it all.. anyway, what the frick made this happen? It's happened more than once to me too. I cleared the CMOS and that didn't make it go away and I was like well that's just for if OCing goes bad.. (right?) So I put in the drivers CD and I guess flashed the bios. It works fine FOR NOW. But still, what the heck made this happen? There is no reason it should have happened. Can I not just let me computer sit alone doing some work for 12 hours or what? (Heat is not an issue, I have good ventilation)