PSU for old pc

[id_wright]

Will a 400W power supply be enough to run:

Athlon XP 2400+
Asrock K7VM2
2x256mb DDR PC2100
HIS IceQ 9800pro
2x optical drives
2x 80Gb HDD
Audigy LS

Are there any rules of thumb to decide which psu rating to go for?

 

[id_wright]

one of antec/seasonic/ocuk - whichever comes back into stock soonest. my old psu died last week and i want my computer back (if the old one didn't take out everything else with it...)