By the sounds of it your MoBo or your processor is toast, Check to see if any caps on the MoBo are "bubbling", if so u'll need a new 1, if it was your RAM or HDD it would still POST. HomeBoy, if it was his PSU it would probably never turn on, but if that is the case, 1) check to see if the PSU fan spins, 2) make sure the PSU doesnt make a semi hi pitched noise and, 3) shake it to see if anything has blown inside.