Working in photoshop...screens go black, power indicator is off. Push power button to hear "click click" in rapid succession, sounds like a relay in the power supply turning on and off quickly.

Hadn't changed any settings recently, and the only thing that i've ever done inside is add a second hard drive, which has run flawlessly for over a year.

Checked battery...3.6V...good. unplugged...reset PMU...wait 5 min...plug back in..."click click". Reseated graphics card, memory, hard drives..."click click".

Anybody else have an idea of what i should try next?