Welcome Ricardo Pais,
I understand how frustrating it can be when you are unable to boot into Windows after flashing your BIOS, and you are now stuck at the sign‑in screen with a PIN error and no option to use your password.
Before moving forward, I just need to clarify a couple of things:
- Are you able to see any option like Sign‑in options (key icon) or Password at the login screen?
- Do you have access to another device to sign in to your Microsoft account (for verification/reset if needed)?
In the meantime, you can try these steps below to troubleshoot the issue:
Step 1: Force access to Windows Recovery Environment (WinRE)
- Holding Shift > Power > Restart until “Preparing Automatic Repair” appears
Step 2: Enable Safe Mode with networking
- Go to Troubleshoot > Advanced options > Startup Settings
- Click Restart, then press 5 for Safe Mode with Networking
Step 3: Restore Sign-in options via Command Prompt
- In WinRE: Troubleshoot > Advanced options > Command Prompt
- Run the following commands one by one:
-
net user administrator /active:yes
-
- Restart the PC and try logging in with the Administrator account
Step 4: Uninstall recent updates (in case BIOS change triggered conflicts)
- In WinRE: go to Troubleshoot > Advanced options > Uninstall Updates
- Choose Uninstall latest quality update first
I hope the steps above help you deal with your issue.
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