I traded my cousin some really expensive RAM that I happened accross for his old desktop, that he put his graphics card into that he swapped from his newer computer. If I plug the desktop into the wall and try to turn it on nothing happens. If I open it up I can see that the where the wire from the power supply plugs into the motherboard there Is a little light on. So clearly some power is getting somewhere…
How do I go about trouble shooting this, and what tools do I need? I assume at minimum a multi meter? Not really sure what to do, it’s been decades the last time I built a computer.
What wattage is the PSU?
You could try taking the GPU out entirely and see if it gets anywhere. If it runs fine without the GPU it’s probably wanting way more power than your PSU can provide. I doubt that’s the issue for various reasons, but it’s a possibility.
My guess would be the PSU as well. It could be dead, or not plugged in right, or underpowered. Pulling out the GPU is a great idea. At least if it boots that provides some direction.