System won't boot

Not sure on the beep side but this is what the lights code refer too.

Ensure that all hard drive and CD/DVD drive cables are properly connected to the system board.
If there is an error message on the screen identifying a problem with a device (such as the floppy drive or hard drive), check the device to make sure it is functioning properly.
If the operating system is attempting to boot from a device (such as the floppy drive or CD/DVD drive); check system setup to ensure the boot sequence is correct for the devices installed on your computer.
If the problem persists, contact Dell (see "Contacting Dell" in your Owner's Manual).

sounds like hard drive dead or your boot files corrupted and your hard drive has no input power. could be power unit weak or your hard drive could have died..they do wear out.
do you hear any fans spinning? there are fans to keep your pc cool. one big one for chasis and one small on over processor chip(heatsink). if the smaller fan(especially) does not spin then PC will not boot because chip will heat up and break if no fan. system will protect itself from this by not starting. open chasis and check if small fan is working. if not this is cheap fix. if it spins then hard drive or graphics card may be bad, which gets more expensive. shop will charge average of $75 dollars to analyze-just to tell you what is wrong, not to fix it.

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

Fried CPU??? I've had a few Dells where the plastic CPU mounting bracket broke off and the heatsink didn't sit on the CPU properly.

Things to check:

1. Power led on the front of the tower, it should be solid green when on. Flashing Amber is generally an indication of a bad power supply inside the tower
2. Power LED Solid AMBER indicates system is not finishing the power on self test (POST) and you remove all connections from the tower except power and try turning on again. If no change, remove all PCI and PCI-E cards from system, try again, no change replace motherboard.
3. On the back of the tower are 4 diagnostic LEDs near the ps2 ports marked ABCD, after the POST, during a normal boot the will flash in several sequences and with boot is finished all 4 should be green. If they stop an a different pattern, then that indicates a failure Yellow Yellow Green Green indicate bad RAM for example
4. If the LEDs on front and back are Green then the system appears to be booting but the monitor display is not functional

if you're familiar on how to open the computer tower's cover, we need to open it.
before opening the cover, make sure all cables are disconnected from the back of the computer. and make sure that you drained the remaining power of the system.
after opening the computer tower's cover, try to locate the cmos battery. (it's a silver coin like battery), remove it from your computer. wait atleast 10 minutes before placing it back. then try to turn on the computer again.


to open the cover, here's the link for the diagram:
http://tinyurl.com/9ax7f

for the complete manual of the system:
http://tinyurl.com/aqzp3

Hey Tony,
If you haven't already: pull all pci cards:
If you pull the ram, and you get no beeps at post, it's likely the main board. Does the pc beep at all? with or without ram? If not, likely the main board. Sorry. Hope this helps...

• 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 would have to disagree with jerry, while that seems reasonable if the motherboard fan isn't running at all then whether or not the video card is ok is somewhat irrelevant.
I would agree somewhat though, i think the PSU might be a good thing to check to see if it is functional.
when you power it on does the CPU fan start or shudder at least ? that would be my first guess for a problem if you had been having any problems recently

i think it may not power supply problem.it may be ram memory problem.try this,remove your ram and clean it with cloth and restore back.