Mobo: Gigabyte ultradurable 3 - GA-970A-UD3 Processor: First gen I7 3.2GHZ Ram: 8GB Kingston DDR3 1066 Video Card: EVGA NVidia GTX 460 1GB Hard Drive: 500MB 7200rpm x2 (can't remember brand, sorry I'm at work.)
Last week my developer preview for Windows 8 ran out so I put my copy of windows 7 back on the computer. The computer at that point started suffering from frequent freezing and crashing. When I rebooted the computer sometimes it wouldn't find the system HD at all. When I looked at the post screen it seemed to show that it wasn't finding either of the HDs.
Then yesterday when turning on the computer I just got GRUB as a message (not a GRUB> prompt, just GRUB) I haven't had a dual boot of Linux for at least a year.
I loaded windows 7 recovery console from the disk and ran:
bootrec /fixboot bootrec /fixmbr
Which did not help. At that point I just installed Ubuntu 13.04 over the windows 7 install and still received the GRUB post.
I went into the BIOS and switched the Hard Drive priorities and then it loaded into Ubuntu fine. For several days everything was just hunky dory until I installed the Ubuntu version of Steam, install Portal and tried to run it.
At that point the computer froze and after hard rebooting couldn't find the hard disks again. Then after restarting the system it loaded up fine again and no issues since. (I have not tried to launch portal again).
My next thought is to remove the system hard drive and try to use the secondary as the master to see if the primary HD is bad.
I'm sorry if this has been confusing, I'll answer any questions I can.