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Troubleshooting Computers | Tech Info Home Page | Troubleshooting |

To start the troubleshooting turn off the computer, the monitor and any other equipment connected to the computer like printers and scanners. Next check all the plugs on the back of the computer like the power plug the video monitor connector, the keyboard connector and any other connectors used on the back of the computer.

 1) Make sure the wall outlet has power.

Try plugging in a lamp or a radio on the same outlet socket to make sure it is working. If the power outlet is fine then check the cabling. If there is no power try a different wall socket.

2) Check to make sure the power cable is connected to the computer and to the wall outlet.

If the cables are not connected then connect them and go on to step 3.

If the cables are connected then make sure they fit properly and are pushed in all the way.

3) Turn the video monitor On. Turn the computer unit power switch to On

The switch should operate properly and you should hear a definite clicking sound and feel it move. Some switches are the toggle style and others are the push button style but either way you should get a feel that the switch has moved and it changed position

If the switch is not operating properly then it is probably a bad switch. If the switch is working fine then go on to step 4..

4) Make sure the power switch is in the On position.

Check the back of the computer where the computer fan is located ( the fan is normally behind a wire grill or a plastic cover with ventilation slots.)

The fan should be turning and you should feel air moving. It should also NOT make any noises. While you are checking the fan, if you see a build-up of dust it would not hurt to get out the vacuum cleaner and gently clean up the ventilation grill.

If the fan is not operating then the computer's power supply is bad. This needs a trip to the computer repair shop or contact the place where you bought your computer in case there is a warranty that covers the part. Usually the manufacturer of the computer will have a technical support department that can help you identify the problem over the telephone.

If the fan is working properly then go on to step 5.

Note: while you are looking at the power supply, check to make sure that the voltage selection is correctly set to your outlet voltage. 

Click for Switch Picture -

This is a small recessed switch on the back of the power supply that can be set to either 115VAC or 230VAC (Volts AC).  

If you are operating with 115V but have the switch set to 230V your computer will only receive half the power it needs and you will get symptoms as follows.

  • Computer Dead
  • No POST
  • CD light steady on
  • No floppy access
  • Hard drive motor starts, but does not do the familiar click and whirr sounds
  • Monitor blank

(Thanks Ian E.)

5) At this point the computer is getting power and the power supply is probably working correctly.

Check the computer's power light usually located in the front panel. Is the light ON?

If the light is on then go on to step 6.

If the light is NOT on then one of two things is going on.

The light bulb is bad. This does not affect the computer's operation in any way since the light is only an indicator and for troubleshooting purposes it can be ignored. In this case go on to step 6. If the light bulb is good then it indicates either a bad power supply, a bad motherboard or in very remote cases a failed component that is drawing too much power and is causing the power supply to shut off. If an even remoter case a low voltage condition as in a brown out would do the same thing, but you would know of that since lights in the house will be dimmer than normal.

6) Make sure the computer keyboard is plugged in ( if not shut off the computer and plug in the keyboard). Check the indicator lights on the keyboard. Press the Keyboard NumLock key repeatedly and see if the NumLock keyboard light is going ON or OFF. Likewise press the CapsLock key and see if the CapsLock indicator light is coming On or Off.

If the CapsLock and NumLock lights are going On and Off then the power supply is working fine and at least some of the motherboard circuits are working properly and you should continue with step 7.

If the lights are not responding then there is a definite problem as follows:

  1. The keyboard is making a bad connection. Make sure it is plugged in all the way.
  2. The keyboard is bad. Try swapping the keyboard with another keyboard and see if that works.
  3. The power supply is bad. You may go on to step 7 to see if you can further troubleshoot the problem.
  4. The motherboard is bad. You may go on to step 7 to further troubleshoot the problem.

7) At this point the computer should at least be getting power, most likely the keyboard is responding to the CapsLock and NumLock key pressings and the computer's power light is probably on.

8) Turn the computer Off wait 10 seconds and turn it back on.

Does the computer make any beeping sounds?

If the computer makes beeping sounds then you need to go on to the "Troubleshooting Boot Error Beeping Codes" section. The beeps are built-in diagnostic errors and have different meanings for different computers.

If there are NO beeping sounds continue to step 9.

9) Check the video monitor. Does it show anything?

When the computer is first turned on it displays boot-up information such as the BIOS manufacturer, amount of memory and other details. Does anything like that show on the video monitor?

If you see Nothing on the video screen then proceed to step 10.

If you see any the above items, then the power supply is working, the motherboard is working and the video card is working in which the computer is NOT dead but is having a problem booting.

If you get beeps then go to the "Beep Code" page. If you see errors displayed on the screen then go to the Post Error Codes Page.

10) Turn the computer off, wait 10 seconds and turn it back on ( the monitor can be left on )

Does the floppy drive light come on at all?

If the floppy drive does not come on at all then go on to step 11.

If the light comes on and stays on , or it comes and for a few seconds and then goes out it could mean that the hard drive is going out. In this case continue with the "Hard Drive Troubleshooting" page.

11) Listen closely to the computer case for the presence of a hard drive hum, or clicking sounds.

If sounds are heard and the hard drive seems to be trying to work then continue to the section "Troubleshooting computer boot-up problems".

12) If by this point the computer is still basically dead and not responding then there is a problem with the computer that you probably can not diagnose any further. If the computer is under warranty you can probably call the place where you purchased the computer and see if they can help.

For out of warranty situations try contacting the computer manufacturer to see if they can provide you with some assistance.

If you know a good computer repair store you can take it there. You can also place a posting on a particular newsgroup, look at some of the internet help sites or send on e-mail to webmaster on this site explaining your problems.




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