power up problem

turn power on- blue cathode tube light flashes and both power supply fan and processor fan move for a fraction of a second- no display on monitor, no other sound or activity except for small red LED on motherboard remains lit. hold power button for 3 seconds and motherboard light turns off. turn power on again- same thing. (brand new 400W power supply. reseated 512MB stick of RAM. thinking of getting a new hard drive and seeing if that works, old one had RAID issues) anyone else have this sort of problem? any solutions?