Dying Power Supply Signs?

[Raim]

For the past month or two, every time I powered on my PC, there was to signal/power transferred to the monitor. I tried switching out the power cables for both the PC and monitor, to no effect.

Just the other day however, without any changes made, the PC has stopped working entirely. I switched out the cables, surge protector, and tried separate wall outlets. Nothing can get it working again. Was the monitor issue showing signs that the power supply was dying out, and what methods can I use to check for other potential issues?

[stroyal]

All you can do is the same thing a computer shop would do.

You have to substitute parts, for the power supply you have to try yours in a known working computer or try a working power supply in yours.

You can test the memory and hard drive with software, but everything else is tested by the above method, except the motherboard, and that, through the process of elimination, if every thing else checks out, it's the motherboard.

edit
More info needed, like exactly what happens, if anything, when you push the start button.
Specs?
Video card or on-board, or both?
Any expansion cards, or is everything, on-board?
The trouble with computer diagnosis, is the symptoms all overlap, and your monitor problem and or not starting, could be PS, video card, memory, CPU, motherboard, or any expansion card.
They might not even be related, and it is as simple as the start button.
Maybe, I can rule out the hard drive, but then again a short in the hard drive could cause it not to start.