The term "dead PC" means that whenever you press the power button nothing happens.
Please note that the following steps involve removing the casing of your computer tower. If your computer is still on warranty, this may void the warranty. If you still have warranty left on your computer, you may want to consider contacting the technical support department for the manufacturer of your computer before attempting the steps outlined below. Also, please read the article fully before commencing any repairs to ensure that you are confident that you can complete all steps without the assistance of a computer technician.
When attempting to fix a dead computer the following measures can be taken.
Check your power supply on/off switch
Your power supply on/off switch is NOT the same thing as your power button. This switch is located at the back of your PC near the power chord's connection. It can be easily identified by the clear marking of 1 & 0. Ensure that the switch is set on 1. Then try to boot your PC again.
Power supply switch sourced from Wikimedia commons
Ensure the power cable is plugged in properly
This is a common error made by PC users. Sometimes the PC may not be plugged in properly to the wall socket and this can be obvious if you look on the socket carefully. On the other hand you should also take note of the other end of the power chord that is connected to your PC. This end sometimes become disconnected if the PC's power chord is too short and the PC is moved causing the chord to be pulled from the PC's power supply. Simply firmly insert both ends of the power chord to its respective sockets.
Power cable connection to the power supply sourced from Wikimedia commons
Check the voltage switch
If the steps above do not resolve your problems then its time to check the voltage switch that is located at the back of some PCs. It is normally red in color.
Voltage switch on the back. sourced from Wikimedia commons
NB. If your wall socket supplies you with 110 volts then you need to set the switch to 110, otherwise set it 220. If this switch is on the wrong selection, your PC will not boot.
Check your supply of electricity.
Ensure that there is actually electricity flowing from your socket. You may do this by simply plugging in another device that you are sure is working. If after you have plugged in another device and power supply is confirmed, moved to the next step.
Electrical socket sourced from Wikimedia commons
Check your power supply
If your computer fails to start after going through all the measures above then its time to check out your power supply.
Power supply sourced from Wikimedia commons
Your power supply is the engine of Computer. It converts AC current supplied by your wall socket to manageable byte sized DC current that is distributed to all your systems electrical components. If your power supply is turned off or damaged, your computer will not be able to function.
To test your power supply, you need to use a power supply tester to test each of the power supply's connectors. You may also use a digital multimetre to test the power supply, however you will need to know the voltages that are passed through the respective colored wires.
Testing power supply's connectors sourced from Wikimedia commons
Each of the power supply's colored wires produce different amounts of current. If even one of these wires fails the power supply's function can be compromised.
To test the power supply:
1. Unplug the power chord from the wall socket;
2. Open the computer's casing and carefully disconnect all the power supply's connectors from all electrical components. (Motherboard, CD/DVD drive, hard drive, floppy disk);
NB. Do not yank any of the wires themselves while unplugging, hold the hard plastic section of each connector.
3. Plug each of the connectors into the tester starting with the 20 or 24 pin connector.
Power supply's motherboard connectors sourced from Wikimedia commons
4. Plug the power chord into the wall socket;
5. Power up the power supply by using a metallic pin/ paper clip to connect the green and the black wires at the back of the motherboard connector.
6. Check the the LED lights on the power supply tester once it has turned. This will indicate which wire isn't firing (if any).
NB. If after you have bridged the two wires (black and green) the power supply fan fails to turn on. The power supply is faulty.
7. Check the other connectors;
8. If there are indications that the power supply is faulty or you do not have a power supply tester then try using another power supply.
Check your power button / reset button
If after testing your power supply with the tester you can confirm that the power supply is in good working order you may need to take a look at your power button. If your power button or reset button is stuck then your computer will certainly not boot. Examine these buttons, ensure that there is good spring action when you press them. If either of them are rigid, use a sharp implement to release it.
Power and reset button sourced from Wikimedia commons
Check the power connection to the motherboard
This measure is important for troubleshooting a dead system you had previously opened to install or remove components. Simply re-insert the power supply connector to the motherboard.
Check that the power button switch is connected to the motherboard
The power button connections to the system's motherboard varies between models. You may need to check this connection if you have installed a new motherboard within your system. If this is the case then take careful note of your hardware's documentation to ensure that the connections are being done correctly.
Check your processor or its Fan
This particular step should be taken if you have disassembled your computer before and may not have re-assembled it properly.
The last thing that one could consider checking is the processor, to ensure it is seated properly. Additionally, you can check to see if the CPU fan is actually connected to its connector on the motherboard. Some computers will boot if their CPU fan is disconnected, but will shut themselves down once the CPU reaches a certain temperature. Some on the other hand won't boot at all if the CPU fan is disconnected.
CPU Fan sourced from Wikimedia commons
Other Scenarios to face when Troubleshooting a non booting Computer
(NB. Many of the steps outlined will relate primarily to Windows operated systems).
Fixing a computer that beeps but won't turn on.
NB. Most PCs are programmed with a set of beep codes that are activated during the boot process. These are used to communicate the hardware's status at power on. A single been usually indicates that all is well in terms of the system's hardware. The combinations of long and short sounds within these beep codes are dependent on the computer's manufacturer.
If your computer beeps continuously at boot time but fails to turn on or display any messages, you may need to check the memory (RAM).
The computer's Memory sourced from Wikimedia commons
To check the memory:
a. First take careful note of the beep code.
b. revisit your system's documentation or utilize online resources to isolate the exact issue.
If information cannot be obtained for one reason or another you may follow the steps outlined.
a. Unplug and carefully open the system casing.
b. Carefully remove the memory by releasing the hammer at the sides until the memory module slowly pops up.
c. Remove it and them firmly re-insert by pushing down the top edges until the hammers slowly re-lock to the sides.
d. Re-plug the power cable and power up your system.
e. If the beep persists, disconnect the power again, remove the memory and insert it to the adjoining empty memory socket.
f. Power up the system again, if the peep persists then consider replacing the memory module.
g. If after you boot the system again and the beep persists then you may be experiencing a motherboard issue.
Monitor displays "DISK BOOT FAILURE, INSERT DISK AND PRESS ENTER"
This message indicates that your windows Operating system may have crashed, become corrupted, or was incompletely installed to your system.
To resolve this issue you may need to install a windows installation disk to repair or re-install Windows to your system.
Monitor Displays "IDE 0 not found"
This message indicates that the Primary drive is not detected. This usually refers to your hard drive which contains the Windows operating system and boot files. To resolve this issue you may need to either physical re-attach the hard drive to its cable (either data cable or power connectors) or change the drive configuration.
To physically re-attach the hard drive:
a. Unplug the power cable
b. Carefully open the system unit
c. Locate the hard drive and re-attach the IDE or SATA cable (depending on which is present within your system) as well as the power connector.
IDE and SATA hard drive connections sourced from Wikimedia commons
To change the drive configuration:
(Depending on the brand of Bios setting being used)
a. Press the power button to boot the computer;
b. At the very first splash screen press the F2, F12 or Del (depending on model);
c. You have now entered the bios settings
Bios settings sourced from Wikimedia commons
d. On the majority of computers, this interface may allowed you to navigate using only the arrow keys.
e. Navigate to advanced and ensure that your hard drive is selected as IDE 0.
Monitor Displays "CMOS settings wrong"
This notification indicates that the Cmos settings that are stored on the bios chip is incorrect. Most often this refers to the systems time and date. Some computers will not boot if the system time and date are incorrect.
To change the CMOS settings:
a. Enter the bios setting as illustrated above.
b. Navigate to advanced and then use the function keys illustrated at the bottom right hand corner or bottom of your screen to change the date and time.
Bios settings sourced from Wikimedia commons
c. When complete press F12 or Esc to save and exit.
Monitor displays "Windows could not start because the following file is missing or corrupt."
To resolve this issue, insert a Windows bootable disk and run set up. (This step will more thoroughly dealt with in another article).
If all the steps outline above fail then:
a. Try inserting the keyboard into its port firmly. (This step is for older computers that will not boot unless a keyboard is inserted in the keyboard's DIMM or mini DIM ports.