Dimension e521 black screen no video signal

If you mean the power button just flashes green but it does not power on then your motherboard might be the issue. Remove any PCI cards like modem, video card, sound card, etc... Remove the memory modules and disconnect cables to CD/DVD drives. In other words just have the power supply and motherboard connected and see if the power light stays solid green. If it does then start re-inserting cards and connecting drives etc (WITH POWER DISCONNECTED) to try and isolate the problem. If not then your motherboard is probably defective and needs to be replaced. Also plug the computer directly into the AC wall outlet.

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

I think your problem is your memory or video card.

Below are some steps that I recommend.

When you plug in the power cord is there any lights whatsoever on the computer?

When you press the power button do you hear fans running, hard drive spinning, lights on the computer, hear any beeps or lights constantly blinking, hear the DvD/CD drive click and the light on the drawer of the DvD/CD turn on for a second or two? If so the laptop is trying to boot or may have booted, but the screen is not showing for some reason.

Beep tones and blinking lights tells the technicians what is going on with the computer and why it is not booting. Most times it's a motherboard issue when you hear beeps or blinking lights continuous. Most times the problem is with the memory or Video Card. Count the Blinking Lights or Beeps and take note of their pattern (1 Long or 1 Long followed by 2 Short).

Maybe your power cord is bad if you don't get anything to happen whatsoever when you press the power button.

Maybe you have a Static Charge Buildup. Remove the Power Cord, then Press and Hold the power button for 30 seconds. After 30 seconds plug the power cord back in and hit the power button to see if it boots.

Maybe your memory is bad or the memory slot is bad.

Remove the Power Cord, Open the Case and remove one of the memory chips. Set the chip aside then try rebooting the computer. If it boots, then you know the memory chip you set aside is bad so mark an x on it with an ink pen. If it fails to boot then move the chip to the next memory slot and try rebooting. If it fails take the chip out and set it aside, then put the other chip in and try booting it in both slots. If it boots, just to verify that the chip set aside is bad, mark an x on it and put it into the open memory chip slot and try booting.

Maybe your power supply is bad. Sometimes there is enough power to make the power light or some other lights come on but not enough power to make the fan turn on or hard drive spin.

Below are links and info I found from Dell's Website based on your model.


http://support.dell.com/support/edocs/systems/dime521/en/SM_EN/specs.htm

Controls and Lights Front of computer:

Power button - push button

Power light
green light - Blinking green in sleep state; solid green for power-on state.
amber light - Blinking amber indicates a problem with the power supply inside the computer. If the system cannot boot and there is a solid amber light, this indicates a problem with the system board (see "Power Problems" in your Owner's Manual).

Diagnostic lights
four lights on the front panel (see Diagnostic Lights.)

Standby power light
AUX_PWR_LED on the system board

Hard-drive activity light
green light - When the computer is reading data from or writing data to the hard drive.

LAN indicator light

green light - Solid green indicates that a LAN (local area network) connection is established.

http://support.dell.com/support/edocs/systems/dime521/en/SM_EN/adtshoot.htm#wp1056411

The 123 lights on tower translates as:

Routine system activity subsequent to video initialization.
Watch your monitor for on-screen messages.

Disconnect the video cable from the computer and see if you get floating color bars on display. If not, your monitor is defective.

First When you power up the computer press F1 or F2 or del or ALt+F2 to enter in bios.Then make sure harddrive is detected.
If you harddrive is not detected or you can't see any display on screen then open cpu cabinet.
Reattach the RAM memory ,both connection to harddrive .Reconnect processor and it's fan pull cmos cell from motherboard for 10 minutes.Remove pci card or vga card if any then check.Make sure motherboard is not ground with cabinet.
Let me know if you need further assistance.
Thanks for using FixYa.

Hi,

Its seems like your RAM is not working properly, so once you replace the this RAM and check it, you problem should be resolve.

Regards

Ashly

if its a flashing amber check power connection.

Input power has been confirmed? From your home outlet? Or from your computer power supply? I think your computer power supply is bad.

remove the new memory first. if that does not help you may have some a virus, indicated by safe mode workng fine. One other thing i found would do that is a damaged Hard drive, not to likely here because safe mode works.

you video card is not working.... if you have onboard video use that until you have installed the driver for your add on video card