frustrating laptop problem

[melvin26]

I have a samsung r720 laptop. There was a problem with the power jack. I plugged it in and something blew. I sent it to some dude who charged me 500 quid to fix. when I got it back.. I plugged it in and the less came on but when I pressed the power button. nothing happens. I suspect that it's either the motherboard or the lid switch. .Please help

 

[popatim]

For 500 quid I'd be taking it back for him to fix right...