Power issues

I built a Core i7 system 3 months ago. It ran fine, then, and for 3 months, til today.
I'm not sure I've seen anything like this, but it is late, and I've only looked at it for about 10 minutes.

I leave this tower on, running ubuntu. (fine for 3 months)
Today when I return, the mouse and keyboard don't wake the machine.
Checked the batteries, they are fine.
I figure oh well, a reset doesn't hurt.
That when the weird power flickerings started.

I can only judge by the leds in the fans, but the power cut out, then back in, then out, then back in.
No response on the monitor.
I haven't pulled out a volt-meter yet, that's my first plan.
But, I checked all the external cables, unplugged and replugged power.
Initially, everything powers up (no monitor response, yet), and cuts out in about one second.
Then after a few seconds it powers up again, glows for ~30 seconds, then cuts out for 10 seconds.
Fearing these voltage spikes might harm something, it takes the hard switch on the PSU to stop these cycles.
After flipping the hard switch, the power tries to come up again, then cuts right out.


These intervals are rough measures, but seem consistent. As in, every time I unplug and switch on, it seems to follow this pattern.

Does this sound like anything right away?
My first suspect is the power supply.
From there, where do I go?
Does Core i7 have a history of such problems?

It seems like the wall is supplying okay. I have a large stereo on the same surge protector and its clock hasn't reset or anything... still plays fine.

It's a PC Power & Cooling Silencer 750 (owned by OCz, I think the package says)

Is there a hardware button to reset BIOS? I never see anything on the monitor, or get a chance for input.

I'll try disassembly this weekend.

Thnx!