there is no power indicator and you cannot hear any cooling fan

chances are that there is insufficient power to the computer. Use a Voltmeter and confirm that there is adequate AC voltage at the wall outlet.Check the AC cord next to make sure it isn't loose or disconnected. See that the master power switch at the power supply is turned on and connected properly.Check the power supply fuse.The main fuse may have opened.Replace any failed fuse.If the trouble continues,try another power supply.In many cases, a poor quality power supply will allow voltage transients to pass through and damage the motherboard (preventing and any system activity)-- though this rarely damages the CPU or RAM.If a new power supply doesn't correct the trouble, replace the motherboard if necessary...

Any doubt comment here