CMPSU-620HX: Part Malfunction?

Hello,

I have a PC using a CMPSU-620HX that has suddenly stopped working.

Upon power up, there is no POST at all. All fans, save for the PSU, are immediately ramped to max speed including the video card, and will not do anything until I manually turn off the PC. The CD/DVD drive is also responsive and can eject/close.

Out of curiosity I opened the case to check if everything was spinning correctly. I noticed the PSU's fan was struggling. It looks as if it's trying to spin, but can't. Also, the red light on the back of my video card (5970) is on, which is said to mean that the unit is not receiving enough power.

My gut is telling me that all of these factors point to a PSU problem, but I can't be sure. I wanted to ask here first to see if I should even bother with an RMA process. I believe the unit was purchased at NewEgg in 06/07, so it should be within the 5 year warranty.

I just thought I'd add that this PC setup has been running fine for a few months now. The PSU itself is a bit over three years old. Mysteriously stopped working for unknown reasons.