My son tried to install drivers and a new USB mouse. Immediately a message "something about a conflict" popped up and the keyboard became unresponsive. He tried rebooting, still keystrokes have no effect--so he can't log in to remove or reset the driver. F2 during startup doesn't take you to a BIOS screen, instead, it brings up "Windows Boot Manager" (We own 2 of the same model computer and F2 is the proper key for BIOS) F10 works normally Keyboard uses serial port. Would removing and reinstalling the CMOS battery be of any use? Please help.