Greetings,
I'm heading to the store in about 30 min to grab a UD3H & 5H shortly. This is a great board, so hopefully we can help you figure this out.
This behavior can have many causes. You need to be systematic in your troubleshooting, make a change, and test one at a time sort of thing.
The first thing to do is recheck all of your connections
Ensure the MB isn't grounding itself to the case
After, I would remove everything except CPU from the board
Use on-board video
See if it will start and run without looping (it will beep)
Now start re-adding one component at a time (stick or ram) etc
Continue testing
Add the vid card last
Verify health of PSU (a weak or failing power supply can cause this behavior)
If it has more than one rail, ensure connected components are distributed evenly
If nothing appears defective, memory is tested and working, I'd remove the CPU and RAM and examine the CPU and memory sockets for damaged or bent pins. I realize the above steps are sort of a catch all, but this is how you can quickly determine what's wrong.
