Function keys such as brightness and sound no longer work

[hajime]

Hi, I installed Windows 7 64-bit Enterprise on my Bootcamp partition few months ago. It was working fine. All of a sudden, the function keys such as brightness and sound no longer work. Know how to fix it?

 

[simsaladimbamba]

Looked at the Boot Camp Control Panel yet to see, if those functions are deselected somehow?