Computer Diagnostic

My Computer Wont Turn On! Troubleshooting Tips

February 14, 2024

My Computer Wont Turn On! Troubleshooting Tips

Having your computer suddenly stop turning on can be incredibly frustrating. However, with some basic troubleshooting, you can often diagnose and fix the issue yourself. Here are some tips for troubleshooting why your computer won’t turn on:

1. Check Your Power Connection

The first thing to check is whether your computer is getting power.

Make sure the power cable is firmly plugged into the wall outlet and the back of the computer. Jiggle the cable connections and press them firmly into place.
Try using a different power cable if you have one available. The cable could be faulty.
Plug the computer into a different wall outlet that you know works. You may have a faulty outlet.
Check the power strip or surge protector if you’re using one. Make sure it’s switched on and functional. Plug the computer directly into the wall outlet to test.
Press the power button on your computer case to ensure the button itself isn’t stuck or broken.
Check the back of the power supply and make sure the voltage switch is set to the correct voltage for your region (115V in North America, 230V in Europe).

If the computer still won’t start up, the issue likely isn’t with the power supply or cable.

2. Check the Motherboard Connections

Open up the computer case and check that all the motherboard power connections are secure. Make sure the 24-pin ATX power connector is firmly plugged in.
Reseat the 4 or 8-pin CPU power connector on the motherboard.
If your motherboard has any other power connectors, like a 6 or 8-pin PCIe connector, make sure those are plugged in properly as well.
Check the SATA and power connectors for all hard drives and SSDs. Reconnect any that may have come loose.
Examine the motherboard for any damaged capacitors. Bulging or leaking capacitors can prevent powering on.

Reconnecting loose motherboard power cables is a common solution for power issues. If the connections are fine, it’s likely a different hardware problem.

3. Remove Extra Hardware and Peripherals

Unplug all external devices like printers, scanners, cameras, and USB drives.
Remove any recently added internal hardware components, like extra RAM, expansion cards, and hard drives.
Disconnect all but one display if you have multiple monitors.

Booting up with the minimum required hardware can isolate problems caused by faulty peripherals and components. If the computer works after removing extras, plug them back in one at a time to identify the problem device.

4. Check the RAM

If you recently installed new RAM, remove it and try booting with the original RAM only. New RAM can be incompatible or faulty.
If you have multiple RAM modules installed, remove all but one stick and try booting with each one individually. One of the modules may have failed.
Try reseating the RAM by removing it fully and firmly pushing it back into the slot until it clicks. The connections can come loose over time.
Check for dirt, smudges or oxidation on the metal RAM contacts. Clean with rubbing alcohol if needed.

RAM issues are a very common cause of startup failures. Reseating or trying individual sticks often resolves RAM-related no power problems.

5. Reset the CMOS Battery

The CMOS (complementary metal-oxide semiconductor) battery powers the computer’s BIOS settings. Resetting it can fix some startup issues:

Unplug the computer and open the case to access the motherboard.
Locate the circular CMOS battery on the board, usually near the RAM slots.
Remove the battery from its holder for 15 minutes before reinserting it. This will reset the CMOS to factory settings.
Some motherboards have a CMOS reset jumper or button instead of a removable battery. Consult the motherboard manual on how to reset the CMOS.

Resetting the CMOS will erase any custom BIOS settings. After clearing the CMOS, access the BIOS again to reconfigure any settings changed from default.

6. Test the Power Supply

If the computer partially powers on but won’t boot fully, the power supply may be faulty. To test a desktop PSU:

Unplug the power supply from components and remove it from the case.
Find the 24-pin ATX connector green wire and a black wire. Use a paper clip to short the two pins together.
Plug in the PSU and turn it on. The fan should spin if the PSU is working properly.
A multimeter can also test PSU voltages. Refer to the unit’s spec sheet for voltage values.
If the PSU fails testing, replace it with a compatible, high-quality unit from a reputable brand.

For laptops, purchase a compatible AC adapter to test with. If the new adapter works, the original AC adapter is likely faulty.

7. Attempt an External Boot

If the computer powers on but won’t boot, try booting from an external device:

Remove the hard drive and plug it into another computer as a secondary drive using a SATA-USB adapter or enclosure.
If it’s detected properly and you can access the files, the hard drive likely isn’t the issue.
Try booting the computer from a Linux live CD/USB or a Windows installation disk. If successful, the issue is with the installed operating system, not the hardware.
For laptops, try booting with the battery removed and only the AC adapter connected. Faulty batteries can prevent booting.

Booting externally helps test software issues versus hardware faults. If external booting works, reinstall or repair the installed operating system on the drive.

When to Take it to a Repair Shop

If you’ve tried all of the above troubleshooting steps and your computer still won’t turn on, it’s best to take it to a qualified repair technician. A computer shop can test components like the power supply, motherboard, CPU, RAM and hard drive to identify failed hardware. Repair shops also have access to spare parts for substitution testing. Some issues like motherboard failure may require replacing the faulty component or even the entire computer.