That does not follow, at all.

Voltage regulator failure on the mobo is one of the most common failures.

I meant if there is 5v under load (and I omitted that any dedicated 3.3v line should be checked as well). Power supplies can only be tested under load after all.

Testing PS under load is still testing it upstream of the onboard voltage regulators.

Mobos are hard to test without appropriate jigs to hold them. Given their cost, I for one don't bother.

And of that, probably the most common failure is the caps. Fortunately, modern radial mount electrolytics have a score mark on the non-lead side. Some people have had success looking for bulging or leaking score marks and replacing the caps. There are a number of manufacturers out there whose caps are known for working only a year or so in a switching power supply.

I had the good fortune to find a thread discussing the PSU of my ProView LCD screen, and managed to resurrect it by replacing caps. Exciting for me, because it has no dead pixels.

Oops - I missed that one. I thought the 5 to 3.3 regulators were now put into the same case as the CPU rather than on the MoBo?

It was the mainboard! I bought a new one and now everything's working The PSU and CPU are both fine.. thanks everyone for your help.