P/S Problem??

[mwars]

Hi, I have a possible power supply problem, and a m looking for suggestions. It is an Antec 300 Watt, in a SX830 case. My Asus probe started giving me low-voltage warnings on the +3.3 v leg. My question is, is this definatly a power supply problem, or could it be one of my components screwing things up?

Specs;
700 P!!!@ 933
Asus CUBX
2 Maxtor 7200rpm HD
Teac 540e CDRom
Philips 8x CDRW
Geforce 2 GTS
256Meg Crucial CAS2

Any advice would be wonderful, thanks.