Computer shuts down seconds after starting up - please help!

Question

I'm having a frustrating issue with my computer where it shuts itself down just a few seconds after I power it on. Here are the details:

It's a custom built PC, about 3 years old
Windows 10
Intel Core i7-11700K
16GB RAM
NVIDIA GeForce RTX 3060 graphics card
1TB SSD, 4TB HDD

When I press the power button, it starts up normally. I see the motherboard splash screen, then the Windows loading screen appears. But after just 5-10 seconds of the loading screen, the PC suddenly powers off completely.

Could this be a failing power supply? Or maybe the CPU is overheating?

If anyone has suggestions on what could be causing this or other troubleshooting steps to try, I would greatly appreciate any advice! Let me know if you need any other details about my system.

Thanks in advance!

allin4 · Answer

Here are some potential causes and troubleshooting steps that might help you diagnose and resolve the problem: Potential Causes Power Supply Unit (PSU) Issues: A failing or insufficient power supply could cause your PC to shut down unexpectedly. Overheating: If the CPU or another critical component is overheating, the system may shut down to prevent damage. Faulty Hardware: A malfunctioning component such as RAM, graphics card, or motherboard could be the culprit. Software Issues: Corrupt system files or a problematic driver could also cause the system to shut down. Troubleshooting Steps 1. Check Power Supply Unit (PSU) Inspect Connections: Ensure all power connections are secure. Test with a Different PSU: If possible, try using a different power supply to see if the issue persists. 2. Monitor Temperatures BIOS/UEFI: Enter the BIOS/UEFI setup during startup and check the temperature readings. Thermal Paste: Ensure that the thermal paste between the CPU and the heatsink is applied correctly and hasn't dried out. 3. Check for Hardware Issues RAM: Reseat the RAM sticks and test each one individually to rule out faulty memory. Graphics Card: Ensure the graphics card is seated properly and test with a different GPU if available. Motherboard: Look for any visible signs of damage or burnt components. 4. Software and System Files Safe Mode: Try booting into Safe Mode to see if the issue persists. If it doesn't, the problem may be software-related. System File Check: Use the sfc /scannow command in the Command Prompt to check for and repair corrupted system files. Event Viewer: Check the Windows Event Viewer for any error messages or warnings that might provide more information. 5. Other Checks CMOS Battery: A failing CMOS battery can cause startup issues. Replace the CMOS battery if it’s old. External Devices: Disconnect all non-essential external devices to rule out peripheral issues. Next Steps Replace PSU: If you suspect the PSU is the issue and have a spare, try using a different one. Clean and Reseat Components: Clean dust from components and ensure all are securely seated. Professional Help: If you’re unable to diagnose the issue, consider taking your PC to a professional technician.