No Video And No Boot

Hello, My computer is custom built and i havent had it for more than a year, recently my cusin gave me a new processor (intel dual core 1.5ghz) so i decided to upgrade to that from a intel pen 4 3.0ghz. when i replaced the processor and latchd the cpu fan in correctly i got no video output. (my graphics card was glowing which it normaly does) every thing in the computer was running properly just no video. So i said screw the dual core i'll build another computer for that. i put my pen4 back in and latchd the fan back in. when i startd the computer back up it booted up with no problem till it cut its self off, so i checkd the fan and i didnt put one of the latches down properly. After latching again it in i turn my computer on and....:(. no video no HDD light, the fan was runing my graphics card want glowing and the cards fan wasnt spinning im thinkn its my mobo.