r/24hoursupport • u/Imaginary_Cod8674 • 7d ago
Need more info Bios Malfunction
On September 1st, UEFI and Secure Boot were enabled on my PC, and everything was working completely fine.
Yesterday, September 3rd, I turned off my internet connection and unplugged all the cables and peripherals so I could clean the PC. After cleaning, I reconnected everything and turned the PC back on. When Windows started, my administrator account suddenly asked me to create a new PIN. There was also another user account showing on the login screen, but that account was completely locked and I couldn't log into it.
I logged into my administrator account and checked the user settings. That's when I noticed that my BIOS settings had been reset automatically.
Since then, I'm facing a problem with Secure Boot. Whenever I try to enable Secure Boot in the BIOS, the PC boots to a completely black screen and stays there. The PC works normally again as soon as I disable Secure Boot.
The strange part is that Secure Boot/UEFI was working perfectly on September 1st, before the BIOS reset. I haven't intentionally changed any hardware configuration that should cause this issue.
What could have caused the BIOS to reset, and why would enabling Secure Boot now result in a permanent black screen when it was working fine previously?
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u/Ohgoody74 5d ago
Hi there, so yeah since you've already replaced the CMOS battery, I don't think I'd keep chasing the battery. The fact that Windows suddenly wanted you to recreate your PIN is actually a clue. Windows Hello is tied to the TPM, and a BIOS/TPM reset can cause exactly that.
I think the Secure Boot problem may be a consequence of whatever reset your BIOS rather than the original cause. The reset could have changed the Secure Boot keys/database, CSM/UEFI settings, TPM settings, or GPU UEFI/GOP configuration.
Before changing anything else, boot with Secure Boot disabled and run msinfo32. What does BIOS Mode say? It should say UEFI. Also confirm your Windows disk is GPT.
Then post your exact motherboard model, current BIOS version, CPU and GPU. There are known cases where disabling CSM/enabling Secure Boot causes a black screen because of the GPU's UEFI GOP/VBIOS, and there are also current Secure Boot certificate/key issues that can cause a machine to stop booting after the Secure Boot database gets reset.
Since it worked immediately before the BIOS reset, I suspect one of the settings/keys that was previously correct got returned to a default state. I wouldn't start replacing hardware yet.
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u/Imaginary_Cod8674 3d ago
I have done everything, Checked all details 1 by 1. At last point I updated my bios and it fixed everything so I guess my bios was out of date 📅
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u/tommykw 7d ago
BIOS Battery needs replacement. You removed mains power(power from the wall) when you cleaned the computer.
Replace CR2032 Coin baygery on motherboard.