power supply or hardrive bad?

[sabrewu|f]

Completely randomly i will go and turn my PC on and sometimes the hardrive will not be recognized. It will say it's a 571 gig hardrive or something crazy like that. Now if i shut my PC off, wait a minute and try again. it will work just fine.I have run a hardrive diag. tool, everything checked out with flying colors.
System:
P4 prescott 2.8
x700 pro
400 watt psu forton source(checked out okay with my psu checker)
(2) 120 MM fans
gigabyte rocket cpu fan
belkin wireless card

I called my motherboard manu. and they told me i need a bigger PSu that maybe the one i have isn't big enough, it's ran fine for a year till now. Any help, suggestions please.

 

[bball4life]

screw the mobo manufacturer, its probably a problem with their mobo and they know it.

No but seriously I doubt it is your psu, especially if it has been working fine, a psu should really affect if your hdd is recognized or not, but then again what do i know. And a 400 watt psu should be more than enough for your system specs, unless there is something you arent telling us like you are powering 20hdd with it