Has my PSU died, taking everything with it !?

[Pranksterr]

Came back to my desk to find PC totally dead, no lights, beeps,fans and after various methods of trying to get power into the system and new power leads, no luck.
So after getting a new PSU, OCZ 550w ZT, mobo light comes on. But, after the system booting up for a sec, no beeps but fans spin, system powers down but then starts up again for a second ect.
Orginal PSU was a 600w, but i have tried booting with various case fans, disk drives and even GPU disconnected, which actually did get an error beep, still the same result as above.

Thoughts ? thx

Asus PKC
E8400
8800GT
4gig ram

 

[Plec]

Reset the CMOS and see if you can get into the BIOS. If you can load optimised defaults save and exit.

Re-enter BIOS - and place in the stock setting for your setup.

If not try a skeleton setup outside of the case (cpu, 1 stick memory, gfx) - and short the header pins and see if there any signs of life.