you have to go back to basics - something attached to the pc is stopping it - remove every cable from the motherboard and if more than 1 stick of memory just leave 1. Remove the graphics card as well. Plug the cables from the psu into the mobo only and see if you now get any beeps. Should be plenty as with no graphics card it will be telling you that. If you get beeps then add 1 device at a time ie graphics card. and so on. By the way do you have any usb cables attached these have been known to stop a system dead. If so take them out first and try booting again.