Hey Tash. Just saw the post. Makes me (hate to say it) feel a little better, because I myself just had that problem three days ago. I posted around here, but no one really helped out.
I oc'ed a 1.6 to a fsb of 144 with the memory up around 384 mhz. It was running smoothly, until I messed with some fans in the case, turned it on and it bluescreened. After bluescreening, I got the "recovered from a serious error" message at every reboot. I brought all the levels back to default, with no oc, but kept getting that same "serious error" message. The pci/agp was locked in, so it shouldn't have been the hard drive. The only thing that I could figure is that mymemory wasn't up to the job, and it some how compromised the operating system (is that possible?) I just re-loaded, and it fixed the problem. Extra bit...I was playing around with super aggressive memory timings (pc2700 @ 1.5, 2, 2, 5) and it brought up that "recovered from a serious error" message. Dropped back down to 2,2,2,5 and it didn't happen again.
Sorry to be so long-winded, but I hope this helps you at all. Like I said, I think it's the memory.
-rsrvoir