EMACHINE W305

I'm not really sure which computer you actually have but if there is a constant beeping when you apply power check the RAM it may have moved int he Socket/s slightly and not be making proper contact.

If this has a Video Card as apposed to On Board Video try removing and replacing the Video Card as sometimes the card can move int he socket and stop working.

If neither of those do the trick replace the Power Supply as this brand has a reputation for using poor quality Power Supply Units.

Col

Test the Power Outlet or Power/Board by plugging in a radio or lamp. Try another Power cord/lead if you have one.

Turn off and remove the power plug from the back of the PC and disconnect the monitor cable. Ground yourself by placing the back of your hand on the Power Supply Unit and not moving your feet. By not taking this precaution it is possible that you could inadvertantly cause damage to the PC from an electrostatic discharge.

Carefully remove and clean the golden edge of each memory stick with a soft rubber/eraser, remembering not to touch the golden edge of the memory stick. Check with one stick at a time, remembering to disconnect the power from the PC between switching the memory modules.

While you are in there remove the Video (Graphics) Card and clean the golden edge as well. Reinsert it and reconnect the monitor when you are ready to start the PC.
If the Fans spin freely when you give them a spin they are probably OK. If there is resistance replace them.

Remove the Power cord from the PSU to discharge the Capacitors in the Power Supply. Then press the Power button for 10 seconds to discharge the Capacitors on the Motherboard. See if it will start. If it does start you can replace the (PSU) Power Supply Unit as it is faulty.