Hint of power then dead.

[Elvio]

Desktop PC. Gigabyte Motherboard, P4, 3.2ghz
Built myself and worked fine for 6 months.
Now I have a problem with powering-up.
It powers-up for 1 sec then stops. This is enough to turn on the LED on the motherboard, spin all the fans etc.
This 1 sec. power-up then is cyclical. It keeps on initiating a power-up every 5 secs.
It did this a few times last week but after 3 or 4 attempts to power-up it then did power-up. Now it doesn't power-up, it just keeps on trying without success.
I appreciate your help.

 

[Phantasm66]

Strip the machine down, so that its just the motherboard, RAM, graphics card and CPU and PSU.

Any of of these components could, I guess be faulty. Start testing good known components in there in their place, starting with your PSU which is probably the first main culprit.