problem with new mobo\cpu.. please help

I recently purchased a new Motherboard and a new cpu. I have had lock up problems constantly. Sometimes it will run for 2 hours. Sometimes 2 seconds. But it always locks up. I've tried swapping out every component(vid card, sound card, hard drive, cd rom, disk drive, etc.)and even tried multiple operating systems (win98/win98se/win2000pro), but nothing has worked with this new mobo/cpu combo. It doesn't seem to be an overheating problem, because my pc doesn't get above 65 degrees, according to BIOS. The only thing that I can think of is that I'm not supplying enough power, as my power supply is only 250watt. Here are my system specs:

ECS KT133A
Athlon(3) 266 1.2ghz
256 mb pc133 dimm chip (micron cas2)
Geforce 2 GTS 32mb
a couple of nic's
Maxtor 40gb hard drive
Creative Sound Blaster Live!
generic disk drive
50x cd rom

Should I go buy a new power source? I'd hate to waste the cash, if power inadequecy couldn't be the source of my lock ups. Thanks in advance.

If you can live without it, I recommend you rma the motherboard back to the vender. It may take 2-4 weeks to get a new one, as the old one will have to be tested. You might be wasting your money on a new power supply. I use a 235 watt sparkle, and have my 1.2 running at 1.33 with no problems. What brand power supply do you use? Are you overclocking?