Very helpful comment there, digital.
Not everyone can afford to take a baseball bat to a new machine. No matter how tempting.
I will again say check those power supplies. I reckon that is where the problem is. If it's a brand new machine still under guarantee, send it back with a note saying there is a possible component power supply conflict resulting in the machine hanging, and they should check that first.
Replacement of the mobo on a new machine is pedominantly unnecessary.