Keyboard works in BIOS but not at windows 7 password screen

I have a brand new Asus motherboard with 16 GB DDR4 ram and i5 processor .

I use old HDD with windows 7. But I am not able to enter password as keybord is inactive at the windows 7 password screen. The numlock light goes off. However I am able to use the same keyboard at BIOS.

Please help. Thanks

Posting in case someone else arrives here. I had the same problem (Mouse and KB working in BIOS, but in Win7 mouse was OK but no KB). Eventually found this solution (on YouTube!) that worked for me: https://www.youtube.com/watch?v=nvyQXaf7X6Y

In short, use the on-sceen keyboard to regedit the UpperFilters key for the following three registry entries to be "kbdclass":

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class{4D36E96B-E325-11CE-BFC1-08002BE10318}

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Control\Class{4D36E96B-E325-11CE-BFC1-08002BE10318}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4D36E96B-E325-11CE-BFC1-08002BE10318}