Sounds like there may be a short somewhere- make sure the power connections are all good, and that there's no screws, loose wires or anything like that. Something similar happened to me- it turned ou it was my sound card somehow went bad and was shorting my system (I found this out by removing every card and unplugging every drive so all that I has was the graphics card, CPU, and RAM. Then I added each piece back until I found the culprit).
Also, you might want to check to make sure the PSU isn't dead- you can do this by unplugging the power connector from the mobo, and then use a paper clip to insert in the pins on the connector (between the power pin and a gound pin). Here's a link that I found that has the basic info:
LINK
Was your friend trying to overclock and went to high? If so, there should be a jumper on the mobo that would let you clear the CMOS back to default (that happened to me as well).