MY COMPUTER WONT TURN ON  

the light on the motherboard comes on and the lan light blinks. the power button is connected to the right pins but nothing happens when i hit the switch. would it be the motherboard or power supply or??

Check that memory and processor are correctly installed. Check that everything's properly plugged. Unplug all drives (IDE, SATA, floppies) and all cards and try again. Then plug shit one by one and see what breaks it.