Sounds like you forgot to put the case spacers between the motherboard and the case tray.
Did you put them inbetween or is the board just screwed straight to the metal case?
I probably get 2-3 customers a year doing this and they wreck every last part of their system usually since it all shorts out and becomes live, hence the fans spin but nothing else happens.
Take out the board and rebuild it, if you forgot the spacers you may be lucky to have a few parts not blown.
ok, figured it out, it turned out to be a faulty power supply unit
replaced my rosewill 530w with a corsair gs600
Thanks Rosewill for making me waste 2 whole days worrying that I fried my motherboard. :|