Menu accelerator keys (underline) not visible

This probably has an easy answer, but haven't found it yet.. I recently
got a new XP machine at work (SP1). Before this, every application's
menu showed their accelerator keys with an underline under one letter in
the word. E.g. in "File" the "F" was underlined.

On my new machine, NONE of them show! I understand that they're still
functional, but I want to see them. How to get that back?

Thanks in advance!
.