But in my experience it's rarely the CPU today. It can be simple things like a CMOS battery but I find many owners today don't want to try such even if it's a dollar part.
So what to do? Let's hear more about this PC. It may be so old that you can find working replacements for 99 bucks.
Used it just this morning and now some hours later, it doesn't boot anymore, i see that one light is still on(usb 3.0) port but yeah, when i try to boot it, nothing happens. Is my PSU dead? I removed ram and gpu but nothing still. No beeps or anything.
Or is it cpu or motherboard?