Computer not starting can refer to a number of things, from a computer not receiving any power at all, to receiving power but not starting up, to facing booting issues halfway through the startup. As such, we’ve organized the troubleshooting steps into appropriate sections for your convenience.
Before you start, if you made any changes to your system right before this issue began, reverting that change, if possible, maybe the easiest way to fix this issue.
Why Is My Computer Not Starting?
- Power supply issues (PSU, switches)
- Loose connections
- Faulty or damaged components (RAM, Monitor, Cables)
- Misconfigured BIOS settings
- Corrupt system files and drivers
How to Fix if Computer Doesn’t Power On?
When you press the power button, if your computer shows no signs of power at all (no noise from fans, no motherboard LEDs, etc.), the issue is likely with the power supply. Here’s how you can troubleshoot the issue in such cases:
- Make sure that the Power Supply Unit (PSU) switch is ON and the voltage switch is correctly set. Check the outlet, and if applicable, power strip switch as well.
- Check the power cable on both ends to make sure it’s properly plugged in. If you have a spare power cable, switch the cable to eliminate a faulty cable as the potential cause.
- Try a different power outlet. If that’s not possible, test the current power outlet with a different device (charger, lamp, etc.) to make sure it’s working properly.
If none of these was the issue, then it’s time to look inward. Unplug the power cable from both the PSU and outlet and try the following steps:
- Check the cables going from the PSU to the other components and make sure they’re not loose. Keep an eye out for any signs of physical damage as well.
- If the connections seem fine and there are no signs of damage, but there’s still no power, try disconnecting all of the power cables from the motherboard, including the pins. Disconnect all external peripherals (HDDs, keyboards, speakers, etc.) as well.
- Now, reconnect only the CPU and motherboard power cables and test if your computer starts (fans moving, LEDs blinking).
- If it starts, the problem was likely with one of the peripheral devices. Reconnect them one by one until you figure out the faulty one. If the PC still receives no power, though, the issue may be with the motherboard or the PSU itself.
- You can use a multimeter or a PSU Tester to check if the PSU was the culprit. If it does turn out to be the issue, it’s best to replace it with a new one.
How to Fix if Computer Powers On But Doesn’t Startup?
The second scenario is that the computer shows signs of power but doesn’t start up properly. This usually means there’s no display at boot, POST, and Beep codes, or the PC powers up for a few seconds and then shuts down, and so on. In such cases, the issue is usually a problematic component such as the memory module, the monitor, or the cables.
Troubleshoot Display Issues
First, let’s start with the monitor. If the power light on the monitor is ON, here are a few things you could try:
- The PC might just be having issues resuming from Hibernate mode. In such cases, hold the power button for 10 seconds to power off the PC properly. Then, turn it back on.
- Check the monitor settings using the controls buttons located at the back or sides of the monitor. Make sure that the brightness isn’t set to 0 or the resolution isn’t set higher than what the monitor can support.
- If those didn’t help, use the Reset option to eliminate any other misconfigured setting as a potential cause.
On the other hand, if the monitor isn’t receiving power at all, it’s likely an issue with the cables and connections. In such cases, here’s what you can do:
- Disconnect both the display and power cables.
- Check the cables and ports for any signs of damage (sharp bends, tears, bent pins, etc.). If you notice any physical damage, you can try to repair it. But generally, it’s best to swap the component with a spare one.
- If there are no signs of damage, properly reconnect all the cables into the correct ports.
- If your display has multiple input sources, make sure it’s using the correct one.
- Finally, it’s also possible that the monitor itself is the issue. Once again, you’ll need a second monitor to test this.
POST / Beep Codes
Your computer uses POST and beep codes to signal various hardware issues to you. For instance, a double beep indicates a GPU error, 3 beeps indicate a memory issue, and 5 beeps indicate a processor problem.
Using these signals, you can identify the exact problem and troubleshoot it accordingly. POST codes vary according to the manufacturer, so we recommend checking your motherboard manufacturer’s support site for further details on what a specific code means.
Check Faulty Components
The POST / Beep codes will generally indicate what the issue is. But in case they don’t, you’ll have to figure out the faulty one manually. Here’s how you can do so:
- First of all, if you see the motherboard LEDs blinking but the PC doesn’t startup properly, the power button on your case itself could be damaged. To confirm this, you can use the onboard power button or the power switch header pins on the motherboard.
- If the power button is fine, then the issue with some of the other components. To test this, only keep the components required for a startup test and remove everything else from the system. This includes your HDDs and GPU as well.
- First, test the RAM. Remove all the sticks if you haven’t already. Insert one stick into a slot and test if the PC powers on. If it powers on, both the stick and slot are good. Use this stick to test the other slots as well. If all the slots are good, test the remaining RAM sticks as well.
- If all the memory modules worked fine, reconnect the GPU and try to power up. If it works, reconnect the HDD and so on. Continue with this until you figure out the problematic component.
How to Fix BSODs, Freezing, and Booting Issues?
The final scenario is that the PC powers on but doesn’t startup properly due to booting issues. This could mean BSODs, the PC could be perpetually stuck in a restart loop, or stuck in BIOS or Startup settings, and similar errors.
If you encounter a specific error, such as Bootmgr is missing during startup, you can look up that error message online and troubleshoot it accordingly. We have numerous articles that deal with booting errors on our website. We highly recommend giving them a read as they will be helpful for resolving the error you’re facing, as well as any subsequent ones.
If your PC is stuck in the BIOS, resetting the BIOS to defaults generally helps. An easy way to do so is by removing the CMOS battery.
Computers also often get stuck in restart loops. In such cases, the PC should boot to the recovery environment after three failed boot-ups in a row. Once you’re in the environment window, you can use the tools available there to troubleshoot the issue. We recommend using them in the following order: Startup repair > Safe Mode > System Restore.
In case you’re not able to restore your PC to a working state, you may have to use System Image Recovery or reset the PC entirely. In rare cases, even resetting the PC may not be enough if the issue is particularly severe. In such scenarios, you can use a bootable media to recover your files and perform a clean install.
Finally, if you’re unable to boot properly due to a BSOD, the solutions detailed in the sections above will be generally helpful for this as well. However, to fix the issue at its root, it’s best to note the STOP code (ex. BAD_POOL_CALLER) and look it up online.
We have articles about fixing BSODs in general, as well as ones that deal with specific STOP codes on our site. Once again, we recommend giving those a read for detailed instructions to fix the specific BSOD in your case.