The computer just turns on but nothing happens only 3 beeps

what brand motherboard? model number? how many beeps?

You need to be more specific and tell what happens when you plug in the power cord and press the power button. There are a number of reason why a computer will not boot, but if you tell what's going on someone can help you.

Computers don't boot for basically the following reasons, 1) the power supply is bad. That means when you plug it in you don't see any lights, and when you press the power button nothing happens, you hear no fans, no beeps, no blinking lights, no hard drive spinning, no cd drive clicking and nothing appears on the lcd screen.

2) A motherboard issue, usually when this happens you will either see blinking lights or hear beeps. Those blinking lights and beeps are codes that tell the technician what is really going on.

3) Static Buildup - try removing the battery and the power cord then Press and Hold the Power Button for 30 seconds. After 30 seconds put the power cord back in (leave the battery out) and Press the Power Button. If it boots up you had static buildup and can replace the battery, count your blessings and Thank The Lord cuz a dishonest repairman would have told you he had to replace the motherboard for $300

The 3 beeps is an error code. If not in your Dell manual contact their customer service tech department to find out what the beeps refer to and then you be guided accordingly with your repair. Could be a bad peripheral, faulty power supply signal, etc.

3 beeps usually means that either the chipset or the processor is dead. Nothing you can do, take it to a repair shop.

This sounds like a memory error, can you define the beeps. There is a thing called a "beep code" on all motherboards, the website for the motherboard defines what the beeps mean. For example: one long beep followed by two short beeps of continous spaced beeps without a break. chris http://www.motherboardsrus.net

3 beeps POST code (power on self test) means RAM problem.
Reseat the RAM module/s and boot up your computer.
If you have two RAM modules, remove them both and insert one at a time to test them, to determine which module is faulty.
If it still doesn't work then replace the RAM module/s

what you are hearing is a beep code, if its 3 short beeps then its the memory which has developed a fault and it may need to be replaced

Seems heat-related motherboard POST failure. Replace it.

Hi Octane, If you?re not getting any beep codes then something real basic is wrong. To start off I would check the following: -check the new power supply and ensure it is designed for your motherboard. -check the power supply connections to the motherboard, the connectors should mate up exactly to the motherboard connector. -check for shorts (mounting screws against capacitor leads are common), correct grounding and so on. Any of those can cause the same symptoms. -test the power supply in another computer or if not available you can generally pickup an inexpensive tester for $10 to $15 at a computer store that sells parts. -make sure your motherboard is designed to accommodate your processor. I would expect a beep code for this but you never know. Let us know how things go and please don?t forget to rate the posting.