My friend has a 7 year old Desktop which he did not use for last 3 years, now he tried to turn it on which didn't happen.
I just no his CPU, an Intel 1 core P4.
What do I have to do to help this PC turn on?
Dust problem?
Any suggestions?
Could be loose or unplugged power connections, bad power supply, bad motherboard. Too many parts involved to really say, your friend will have to start diagnosing parts to figure out why it won't start.
Unplug the main 20 pin motherboard connector and short out a green and black pin with a paper clip. If the power supply starts up then at least you know it's good.
Also try shorting out the power switch pins on the motherboard to see if it's the power button that's broken.