Fix the problem that the PC turns on but doesn't turn on the screen

1. Screen test

The first point you need to pay attention to is the screen. It is possible that the monitor itself is damaged and cannot display the output of the PC. Try unplugging the cable connected to the PC, if it shows the screen logo or the 'no signal' signal normally, it means the screen is not damaged.

Now securely plug the display cable back in. If the screen is still not displayed, go to the next steps.

2. Restart the PC

Sleep or Hibernate also sometimes causes the computer to not display anything. Please press the restart button on the body to make sure the PC is turned on in the correct orientation.

3. Listen to the 'beep' code to identify the error

Computers are designed to make a 'beep' sound if they encounter some kind of problem. Listen for the beeps as you start your computer and find out what you've encountered. Each BIOS vendor will have a different pattern and meaning for the number of beeps, please refer to the table below to find the appropriate error cause.

AMI . beep code

1. 1 short beep: Timer error
2. 2 short beeps: RAM module is faulty
3. 3 short beeps: RAM module is faulty
4. 4 short beeps: Faulty timer IC
5. 5 short beeps: CPU error
6. 6 short beeps: Keyboard driver is faulty
7. 7 short beeps: CPU/Motherboard failed
8. 8 short beeps: GPU error
9. 9 short beeps: ROM BIOS error
10. 10 short beeps: CMOS error
11. 11 short beeps: Cache error
12. 1 long beep, 2 short beep: Video system error
13. 1 long beep, 3 short beep: Memory test failed
14. 1 long beep, 8 short beep: GPU error

Award beep code

1. 1 long, 2 short: Display adapter error
2. Endless Repeat: RAM Error
3. 1 long, 3 short: GPU error
4. High frequency beep: CPU overheating
5. Repeat High/Low: CPU error

Compaq . beep code

1. 1 short: No error
2. 1 long, 1 short: ROM BIOS error
3. 2 short: Unknown error
4. 1 long, 2 short: Display adapter error
5. 7 beeps: Video card error
6. 1 long beep: RAM module error
7. 1 short, 2 long: RAM module error or RAM connection is not tight

If you still can't determine what's causing your PC not to display the screen, continue with the ways below to try to fix the problem.

4. Clean and reinstall the RAM

If you don't hear any beeps when the computer turns on without a screen, this is most likely due to a faulty RAM module.

If you have installed multiple sticks of RAM, you should remove them one by one and try restarting your computer and find out which one is faulty.

Even other RAM sticks work fine, sometimes they still fail due to dust accumulation. Remove the RAM, wipe it with a dry cloth, and then reinstall it. Make sure the RAM is installed tightly.

5. Reattach the CPU

Note that this is something that you should do carefully and should only do it when you think the screen failure is caused by the CPU. The CPU is found under the main cooling fan mounted on the mainboard. Gently remove the CPU from the motherboard, reapply thermal paste, and put it back in place. You should go through the instructions to remove and install the CPU to make sure the process is safe.

6. Check the power supply unit (PSU)

Even though the PC's lights and fans are still working, that doesn't mean there aren't any problems with the PSU. Insufficient power supply to the display adapter can also be the reason why the PC cannot display the image on the screen. Therefore, you should try installing a new PSU to see if the PC functions are working properly. Also, when plugging in a new PSU, it is recommended to allow another 5-10 minutes for all the capacitors and CMOS battery to recharge.

The error of the computer working but not on the screen is mainly due to loose RAM or RAM error. If you discover another cause for your computer to have this condition, the fix will be a bit complicated. The advice is that you should seek the support of a professional repair and warranty department. Good luck!

Samuel Daniel

Update 24 December 2021