I have a desktop, 256 gigs, have linux installed, ubuntu 10.04, proceeding to upgrade to 10.10, would not accept upgrade, said only "partial" upgrade would work, in process of partial upgrade computer locks up, in attempt to "restart" i hit "suspend" accidentally, computer goes completely dead, no response to keyboard, mouse, power on button, removal of power cord and battery, nothing at all, try different power cord, different outlet, holding power on and emergency pin inlet power on button, nothing, dissassemble power button connection pins to motherboard, reconnect, nothing, computer is completely dead, no response, no nothing, visual of motherboard shows no burnout of soldered connections, try flipping breaker, unhooking all power supply cords to mother board and cpu, nothing, configure exact hookup pattern as this computer, nothing, suspend mode killed computer dead.....ready to throw computer out window and film "destruction of desktop by angry confused human" which at least makes sense other than, "computer completely dead by 'suspend' button"........ready to revert back to ABACUS....yours truly, Antony Cernuto.....

Is there power coming out of the PSU ?
Use a meter and test the leads.