hmmm... this is very weird. Well, the next thing I would try, since you've done the MBD swap, is a more powerful power supply. maybe a 450. Just get one for now for first system and see if it makes a difference. Since both are having the same problem than I would HOPE maybe it was just inadequate power. See what happens from there.
Just realized, do you have 2 seperate mem slots filled? If so, try to boot with just the first slot, so remove one mem module. So now should have just one mem in the first slot and nothing in the others. Then if that doesn't work, swap with the other and try again. Remember, just ONE DIMM in the first slot and then swap with the other DIMM.
If you argue with an idiot he will drag you down to his level and beat you with experience.
I am not a fast writer.
I am not a slow writer.
I am a half-fast writer.