Help for XP PC locked up

[noddy]

I am running XP on An AMD Athlon 2500. The CD rom, CDRW, the mouse and the keyboard have all failed. They have power to the various items and all are vertually brand new. The system boots all ok but I cant get into it. Have checked all connections and they are fine,cables fine,changed keyboards and mouse etc etc but still nothing - any ideas - all will be appreciated.

[merlin]

when you boot do any lights flash on the keyboard(num lock)any beeps from the mobo do you obtain post?check the mobo for capacitors leaning over and for tracking on the board amd do run very hot?also check the psu ?