Registry fault: Can't open on-screen keyboard Vista/Office..

Hi, I need help: I have Windows Vista and use Office 2007 Home and Student.
Today I wanted to use the on-screen keyboard. I got a message that the
registry file/entry for it is damaged and to re-install.
Question: re-install from where? Vista? Or Office? What is the file name?
Does somebody know? If it's part of the Vista - is there a way to install
just that 1 file without wiping everything off my hard-drive? Vista came as
part of the recovery CD I received when I bought the laptop a few weeks ago.
Thank you for your help!!