Hi John Medvec,
If the new password works when signing in to your Microsoft account online, the next step is to verify that the PC can connect and synchronize with Microsoft account services during sign-in.
Please try these quick checks:
- Confirm the new password works at the Microsoft account website from another device.
- Verify the Windows 8 PC is connected to the internet at the sign-in screen.
- Restart the PC after confirming the network connection, then try signing in again.
If the issue continues, please let us know:
- Whether you're signing in with a Microsoft account or a local account.
- Whether the PC has been connected to the internet since the password was changed.
- The exact error message, if one appears.
Please note that Windows 8 reached end of support on January 10, 2023, devices running Windows 8 no longer receive security updates, non-security updates, or technical support from Microsoft. As a result, some account authentication or connectivity issues may be more difficult to troubleshoot on this platform. You may wish to consider upgrading to a supported version of Windows if the device meets the requirements.