I have a dell dimension desktop. It won't turn

A solid green light means the computer is operating normally.

A solid yellow light indicates the power supply is operating normally but the computer is not processing data.

This could mean there is a problem with the CPu or another component on the motherboard.

((A blinking yellow light indicates the power supply is receiving power from the wall, but not functioning properly.
This generally means the power supply itself is bad and should be tested or replaced.))

A blinking green light means the computer is in standby mode.

You should consider visiting Dell Support and downloading the manual for your

your Dell computer. So use the LED power light codes if your Dell computer has them.

hope this helps

An Amber blinking power button indicates a low voltage problem. This can be caused by a defective power supply or a defective motherboard. Since you replaced the power supply, my guess is that the motherboard has a problem.
Just to make sure that nothing else is causing the problem, remove any PCI cards like modem, video card, sound card, etc... Remove the memory modules and disconnect cables to CD/DVD drives. Look at the USB ports to see if any are damaged.

Do you use a surge protector? If you do, try turning off the power supply to the surge protector and switch on again.
There are a number of causes for this problem, the most likely being a PSU problem or a motherboard fault/failure. To check the power from the PSU to the motherboard, you will need a multimeter to make sure enough power is going to the motherboard. Also check the motherboard closely to see if there is any signs of corrosion or blackened areas, which could be caused by overheating components. Check for leaky or burnt capacitors.

Open the CPU cabin remove the RAM.
Clean it with a cotton. Now place it back and check once more.
If it is not working replace SMPS (Power box).

If the POWER Button on the TOWER is blinking AMBER (Yellow) then the most likely failure point is the POWER SUPPLY in the Tower.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817226001

Try a different power supply in the computer if you can. Get a known working one cause its possible that your current power supply isn't putting out the right voltages.

If you try another power supply and you still keep getting the blinking yellow light then that means the motherboard is bad.

try unplugging it and plugging it back in if that doesn't work then try reinstalling it

Use your CD to boot up the computer and recover your operating system

• Blinking Amber/yellow: Initial state of LED at power up.
  Indicates system has power, but the POWER_GOOD signal is not yet active.
  If the hard drive LED is off, it is probable that the power supply needs to be replaced.
  If the hard drive LED is on, it is probable that an onboard regulator or VRM has failed.

i get beeps, but no screen display.