Trouble shooting is the process by which we can solve problems starting from the begining of the chain of situations that could go wrong, in this case if the monitor is not displaying anything we can check if the monitor cable is actually connected to the CPU, so pluggin the power cable to the computer would be a good first step in troubleshooting.
He runs up the stairs, so he needs a total amount of energy = mgh = 5880 Joules.
For the rate: since he goes from zero energy to 5880 Joules over 8 seconds...
Joules/sec = 5,880/8 = 735 W
