My friend started with a running PC which was powered off. When turned on nothing happens. I opened the case and found it full of dust, including the CPU fan casing. It was pretty bad so this may have caused over heating of some parts so after cleaning it up I went through the process of elimination. Symptom - motherboard led is on. When power on switch is pressed the CPU fan spins for a few revolutions then stops, no beeps. Pressing the power on switch again does nothing. Fan will not spin again until the power cord is removed and reinserted. Once again, pressing the power on switch spins the CPU fan for a few revolutions then dies. Replaced the power supply, increased from 300W to 380W. Same problem. I disconnected everything. I now had only the following items in play: motherboard, CPU, CPU cooler fan and RAM. Same problem. Tested power cord to make sure it was getting 120v and the power supply was set to 115v, still no joy. Decided the motherboard was bad. Bought a new motherboard of the same brand, newer model (ASUS P541GT-M LX3) with proper foot print to fit the box. New Intel Pentium Dual Core CPU which included the heat sync & fan. New Patriot 2 X 4-GB DDR3 1333Mhz memory. Again with only the following items in play: motherboard, CPU, CPU cooler fan and RAM. Same problem. HELP!