The laptop keyboard works in the BIOS menu but not in Windows. You can enter the BIOS setup menu and navigate through the menu using keyboard keys. As soon as Windows loaded, the keyboard stops responding.
Possible troubleshooting steps and repair solution:
Most likely this is a software-related problem. If the keyboard works on the BIOS level, it means the keyboard functions properly.
The best and more efficient way to fix this problem is reinstalling the operating system from scratch. Back up all personal data and run the recovery disc or installation CD. There is a very good chance that reinstalling the operating system will make your keyboard functional again.