My mid2010 MacPro is completely useless now

mac Pro mid 2010 only cycles between problem screen:

"your computer restarted because of a problem..."

and the progress screen which is stuck at 80%

loaded. No other choices, ie mac is useless.

Restarts not working.

wont open in Safe mode, wont show alternate

system disks in option start either

I even took out the "upgraded" disk and

still nothing will register. grrrr