My very unexpert unscientific opinion:
If it's a no name 350 watt, I would upgrade to a better one. If the powersupply is by Antec, it's debateable. With a P4 2.53, ti 4200, and 3 cd/dvd dries, I'm very torn. If you have money, go for it. If not, see if it is stable, check the reviews...