I've posted here before about my MDD locking up for no reason, CPU dumps on the screen and not booting. Well, I think I have narrowed it down to the Belkin 4-port USB switch that I'm using. When I have the keyboard plugged directly into the back of the machine, it won't lock. I did this for the entire day and it worked fine. Then, before I went to bed, I plugged the keyboard back into the switch and went to bed. Note, I don't set my computer to go to sleep.
When I woke up, the machine had been locked up since 2:45AM. No screen dumps, nothing. This hadn't happened the entire time that I had been skipping my Belkin switch.
Now I have to manually swap the keyboard between that and the switch which still goes to my pc. (I do win32 coding on it that I cannot do on the mac)