Troubleshooting Guide: Computer Turns On But No Display

If you ever have worked in tech support, or even have a PC laying around at home, there's a more than good chance you have or will into this issue at some point. This is a quick guide to help you out whether you are helping out with a customer in your current job or if you are running into issues on your own.

First and foremost, if a monitor is involved and this is where the issue occurs READ THE MANUAL!

Step 1: Basic Checks for when your Computer Turns On But No Display

As we always recommend, before diving too far into a rabbit hole of troubleshooting always start with the very basics. More often than not, a simple trick can resolve the issue before you find yourself in too deep on the 8th page of Google trying stuff when the resolution was right there in front of you the whole time.

1. Monitor Power and Connections:

• Ensure the monitor is powered on. Look for the power indicator light. This is more relevant if you are plugged into some sort of display. For example, a worker at cubicle plugged into a docking station. Make sure everything is plugged into the right spots and not loose or disconnected. (Happens more often than you would think).

• Check that the video cable (HDMI, VGA, DVI, DisplayPort) is securely connected to both the monitor and the computer.

1. Input Source:

• Verify that the monitor is set to the correct input source. Use the monitor's on-screen menu to select the input that corresponds to the connected cable. For example some monitors will have settings for HDMI, DisplayPort, or automatic. It's worth cycling through.

1. Cable Condition:

• Inspect the video cable for any visible damage. If you have a spare cable, try swapping it out. We've personally seen this in our office many times with USB-C cables. The USB-C connects our laptops to a docking station and for some reason is more often than not the culprit.

1. Monitor Functionality:

• Test the monitor with another computer or device to ensure it is working correctly. For peace of mind this will confirm if the issue is likely occurring from your laptops end or if the monitor has potentially run it's course.

Step 2: Power Cycle

Power cycling can often resolve display issues caused by temporary glitches. When all else fails, reboot everything. An argument can be made this should be step #1 but when an external monitor is involved I usually lean checking the cables first.

1. Turn off the computer and monitor.

2. Unplug the power cables from both the computer and the monitor.

3. Wait for at least 30 seconds.

4. Plug the power cables back in and turn on the computer and monitor.

Step 3: Check for POST and Beep Codes

The Power-On Self-Test (POST) is a diagnostic testing sequence that occurs when the computer is powered on. Beep codes can help identify hardware issues. This doesn't occur too often but this could actually occur sometimes. It's worth checking if the usual checks haven't resolved the issue.

1. Listen for Beeps:

• If your computer has an internal speaker, listen for any beep codes. Refer to the motherboard manual for the meaning of the beeps.

1. Look for POST Indications:

• Some motherboards have diagnostic LEDs or a small display that shows error codes. Check your motherboard manual for details.

Step 4: Check the BIOS/UEFI

Accessing the BIOS/UEFI can help determine if the issue lies with the operating system or hardware.

1. Turn on the computer and repeatedly press the BIOS/UEFI access key (commonly F2, F10, Delete, or Esc) as soon as you see the manufacturer's logo.

2. If the BIOS/UEFI screen appears, it indicates that the monitor and basic hardware are working correctly. Ensure the correct boot device is selected.
   

Step 5: Check Internal Components

Internal hardware issues can also cause display problems.

1. RAM:

• Reseat the RAM modules. Remove and reinsert them firmly into their slots.

• If you have multiple RAM sticks, try booting with one stick at a time to identify if one is faulty.

1. Graphics Card:

• Ensure the graphics card is seated properly in its slot.

• If your motherboard has integrated graphics, try connecting the monitor to the onboard video port to see if the dedicated graphics card is causing the issue.

1. Connections:

• Verify that all internal cables are securely connected, including power cables to the motherboard and graphics card.

Step 6: Check for External Devices

Believe it or not, I've seen this happen quite often when a USB is plugged in when booting on a machine. Sometimes, external devices can interfere with the boot process. When I worked in tech support, you'd be surprised how many times this saved my ass when troubleshooting this issue over the phone. I can't tell you why, but just try it before throwing the towel in.

1. Disconnect all external devices except the keyboard and mouse.

2. Try booting the computer again.

Step 7: Test with Minimal Hardware

To identify if a specific component is causing the issue, test the computer with minimal hardware.

1. Disconnect all non-essential components (additional hard drives, sound cards, etc.).

2. Boot with just the motherboard, CPU, RAM, and power supply connected.

Step 8: Power Supply

A faulty power supply can lead to insufficient power for the components.

1. Ensure the power supply is functioning correctly. Look for any signs of damage or unusual noises.

2. If possible, test with a different power supply.

Step 9: Inspect for Physical Damage

Check for any signs of physical damage on the motherboard or other components.

1. Look for burned components, swollen capacitors, or loose parts.

2. If you find any damage, the affected component may need to be replaced.

Step 10: Seek Professional Help From Manufacturer

If you've gone through all the steps and the problem persists, it may be time to seek professional help. Often times you will need to provide the serial number on either your machine or monitor, but support tends to be pretty good. And by pretty good I mean they will usually let you return your current hardware and be replaced with a new one (If it's under warranty still).

1. Contact the manufacturer’s support team or take your computer to a certified technician for further diagnosis.

Interview Practice

To solidify your understanding, here are some interview questions related to this topic, along with their answers.

Question 1: What is the first step to take when a computer turns on but displays nothing on the screen?

Answer: The first step is to perform basic checks, including ensuring the monitor is powered on, verifying the video cable connections, and selecting the correct input source on the monitor.

Question 2: How can you determine if the issue is related to the RAM?

Answer: To determine if the RAM is causing the issue, you can reseat the RAM modules, try booting with one RAM stick at a time, or use known good RAM sticks to see if the problem persists.

Question 3: What are POST and beep codes, and how are they useful in troubleshooting display issues?

Answer: POST (Power-On Self-Test) is a diagnostic sequence run by the BIOS/UEFI during startup. Beep codes are audible signals that indicate specific hardware issues. They are useful for diagnosing problems with components like RAM, graphics cards, or the motherboard.

Question 4: When should you consider checking the power supply when troubleshooting a no-display issue?

Answer: You should consider checking the power supply if the computer shows signs of insufficient power, such as the components not receiving enough power to function correctly, unusual noises, or if other components have been ruled out as the cause of the issue.

Question 5: What steps can be taken if all basic troubleshooting methods fail to resolve the no-display issue?

Answer: If basic troubleshooting methods fail, you can test the computer with minimal hardware, inspect for physical damage, and ultimately seek professional help from the manufacturer’s support team or a certified technician.