Amber light is showing on power button

It sounds as if your power connector is not seated correctly
See error light codes in this manual
http://support.dell.com/support/edocs/systems/op960/en/setup/setup_en.pdf

1) Switch the system on. Can you tell me if the power button is flashing amber or a solid amber? Please also tell me if you notice any diagnostics LEDs staying lit - these are labelled 1,2,3 and 4 and are near the front headphone sockets
2) Please remove all peripherals at the back of the system and switch the system on. Does this affect the power button LED or diagnostic LEDs
3) Have you added any components to the system e.g. video cards, sound cards etc...
4) Please open the system and remove the following components:
a) Power and data cables from hard drives and optical drivesb) Any PCI/PCI-Express expansion cardsc) All memory from the systemd) The system fan
5) With the above removed, please reconnect the power cord to the back of the system and switch the system on. Please make a note of what happens with the power button LED and the diagnostic LEDs
6) If there are no changes to the power button LED or diagnostic LEDs, please remove the power cord from the back of the system and remove the following components:
a) I/O panel cableb) CMOS battery
7) With the I/O panel cable and CMOS battery removed, please connect the power cord to the back of the system. The system should automatically try to switch on. Do you hear any beeps from the system? If so, can you tell us exactly what you hear?
If you need any assistance with removing these components, please see the User Manual here: http://support.euro.dell.com/support/edocs/systems/op380/en/index.htm
Please keep us updated on how you get on!

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

run a diagnostics on the system, press and hold "fn" key and then turn on the system it will go to the diagnostics mode and then it will comeup with and error or it will show you the malfunctioning component

hey the problem from ram or hard disk cable dutted

Steady amber power LED is indicative of a problem with the motherboard. Remove all external connections except power, remove all PCI Cards, ram, disconnect power from all drives, turn on see if power LED is still steady amber. If it is, more than likely the motherboard has a failure. Also check to see if the CPU heatsink is firmly seated (The plastic retainer has been known to fail causing the CPU to overheat)

Hi there.
Sounds like the battery could be faulty.
The diagnostic procedures from the Dell User Guide are as follows:

Total Power Failure When Using a Battery
If an AC adapter is not connected to your computer, the computer's power source
is a battery. If the battery indicator flashes amber or is a steady amber, the
battery needs to be charged. If the battery is flashing green and amber, the
battery may be defective. To troubleshoot this problem, use the following
procedure.
1. Turn off the computer and peripherals, and disconnect them from AC power.
2. Reseat each installed battery by removing it and then replacing it.
3. Turn on the computer. Does the green power indicator light up?
Allow one minute for the computer to initialize its components before checking
for signs of power.
Yes. Continue to step 4.
No. Use the AC adapter to connect your computer to AC power. If the computer
operates normally when using AC power, go to step 7. If the computer does not
boot when using the AC adapter, see the previous subsection, "Total Power
Failure When Using the AC Adapter."
4. Does the battery indicator flash amber or show a a steady amber light?
Yes. The battery needs to be charged. Go step 5.
No. Go to step 7.
5. Connect the computer to AC power, and fully charge the battery.
For instructions, see the topic titled "Charging the Battery" in the online
System User's Guide.
6. As the battery charges, does the green battery indicator light up?
Yes. Go to step 9.
No. Go to step 7.
7. Is the battery indicator flashing green and amber?
Yes. Your computer may be in a hot environment. Charging the battery in this
condition may affect the life span of the battery. Continue to step 8.
No. The problem is resolved.
8. Disconnect the computer from AC power. Is the the battery indicator still
flashing amber?
Yes. You may have a defective battery. Continue to step 9.
No. The problem is resolved.
9. Remove the battery, and press its test button. Is the uppermost indicator in
the charge gauge of the battery flashing?
Yes. You have a defective battery. Continue to step 9.
No. The problem is resolved.
10. If a spare battery is available, fully charge it, and then install it in the
computer.
11. Turn on the computer. Is the power indicator off?
Yes. Your original battery is defective.

Good luck

The diagnostic procedures from the Dell User Guide are as follows:

Total Power Failure When Using a Battery
If an AC adapter is not connected to your computer, the computer's power source
is a battery. If the battery indicator flashes amber or is a steady amber, the
battery needs to be charged. If the battery is flashing green and amber, the
battery may be defective. To troubleshoot this problem, use the following
procedure.
1. Turn off the computer and peripherals, and disconnect them from AC power.
2. Reseat each installed battery by removing it and then replacing it.
3. Turn on the computer. Does the green power indicator light up?
Allow one minute for the computer to initialize its components before checking
for signs of power.
Yes. Continue to step 4.
No. Use the AC adapter to connect your computer to AC power. If the computer
operates normally when using AC power, go to step 7. If the computer does not
boot when using the AC adapter, see the previous subsection, "Total Power
Failure When Using the AC Adapter."
4. Does the battery indicator flash amber or show a a steady amber light?
Yes. The battery needs to be charged. Go step 5.
No. Go to step 7.
5. Connect the computer to AC power, and fully charge the battery.
For instructions, see the topic titled "Charging the Battery" in the online
System User's Guide.
6. As the battery charges, does the green battery indicator light up?
Yes. Go to step 9.
No. Go to step 7.
7. Is the battery indicator flashing green and amber?
Yes. Your computer may be in a hot environment. Charging the battery in this
condition may affect the life span of the battery. Continue to step 8.
No. The problem is resolved.
8. Disconnect the computer from AC power. Is the the battery indicator still
flashing amber?
Yes. You may have a defective battery. Continue to step 9.
No. The problem is resolved.
9. Remove the battery, and press its test button. Is the uppermost indicator in
the charge gauge of the battery flashing?
Yes. You have a defective battery. Continue to step 9.
No. The problem is resolved.
10. If a spare battery is available, fully charge it, and then install it in the
computer.
11. Turn on the computer. Is the power indicator off?
Yes. Your original battery is defective


good luck

Check to see if there are any loose connections to the memory cards on the memory board. Make sure the data cable to the drives are connected properly. Is the fan in the power supply on?

yep

unplug the system
open the case
look for a battery and take it out
take out the memory (rams)
wait ten minutes
press power button 5 times
put everything back in

and boot it