Is my Mother Board good or did I burn out something?

I accidently plugged in the DC plug into my dual fan cooling unit (that the netbook sits on) which was plugged into USB port & I think it sent power into USB port & burned out something, cause now I can't get screen to come on & I don't hear the drive start up only thing that comes on is the lights in front & I hear the fan start up but doesn't stay on for long. PLEASE HELP ME!! I'm on disability & really can't afford to take it to a shop, I'm hoping I can do this myself. :-) THANK YOU IN ADVANCE ... :-) :-)