Update, ran Memtest86+ for three passes on the RAM currently in the faulty computer, and six times on the four sticks in THIS computer. No errors on either. That sort of leads me to believe that the RAM slots themselves aren't defective either. It seemed to get some use out of the CPU during this test as well, which also leads me to believe that works fine, too. That leaves just the board (unless someone disagrees with what I just said).
And as far as the C: drive switching, I googled it, and I'll run a repair on both drives in a bit. Still would like someone to look through this BIOS screenshots above.
EDIT: Currently wiping the HDD of the other computer. If this doesn't rectify any issue that caddi daddi might have been hinting at, it's almost certainly a motherboard problem, whether physical or some erroneous option in the BIOS.
EDIT 2: I JUST wiped one of my SSDs and booted a fresh install of Windows 7 on it, and my computer booted up! Talking to a friend, he feels that it might have been something to due with a damage file somewhere in Windows, but that doesn't quite add up to me, seeing as how even the SSD that was originally the one in there didn't boot up, and it boots up on this computer. Regardless, I'm going to try a fresh install on this SSD too, and then give it a whirl.
Just asking, but has anyone ever heard of something like this? Installing new hardware somehow corrupting Windows files over several HDDs (more likely BIOS related at that point), and even persisting after going back to the original hardware?
