Windows 10: Keyboard Not Registering Some Keystrokes in Bootup Login Screen

My keyboard has never had this problem in the past but lately I've been forced to use the on screen keyboard as mine will not work well at all to type in my password in the login screen. It is extremely laggy and won't even register some keystrokes even after a long period of waiting.
Once I log in however my keyboard works perfectly fine again so I don't know why this problem would occur only on the login screen and only on bootup (when I lock my computer and unlock it the keyboard once again works fine).
This problem just started happening so if anyone knows a fix the information would be appreciated.
Thanks

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Windows 10- Microsoft account vs Local account

Last feedback - I tried twenty ways from Sunday to get to the Boot Setup menu. When restarting the machine it says to use the F12 key. But that doesn't work... I try tapping it, holding it, etc throughout the bootup process and it still boots straight
to Windows and the locked-out login screen. Thus I can't change the boot order to try and boot from a CD or USB. I'm making a wild guess that the USB keyboard hasn't been initialized yet before the window where F12 is accepted closes. I've tried different
keyboards, different USB slots, and even different keystrokes (using all the other BIOS keystrokes from other machines I've once had).

 

Keyboard Issue

Since upgrading my old HP Pavilion g6 to Windows 10, I'm having issues with my keyboard, especially when trying to login to my computer. My key strokes are displaying letters and/or symbols that I did not type which results in login error message. I can
only use the on screen keyboard to login. The keystroke mishap also occurs when I'm using email, but is not happening while typing this message. Please help to resolve the issue. Thank you!

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