Alright, I've only tried seating it once, I'll take another look at that.
As far as the memory goes, I think I've found the culprit. Here are my test results:
Test 1 (both DIMMs): 2.0V, 2 errors at 835.6 MB in Test 6
Test 2 (both DIMMs): 2.1V, 2 errors at 835.6 MB in Test 7
Test 3 (one...