Johnny Foreigner
Had a colleague from Brussels visit HQ years ago while I was a PFY with Windows 3 days. Used to borrow people's PCs, set the keyboard to French layout, never set it back then borrow someone else's PC, set the keyboard etc etc.
As the junior IT support, I was getting the calls about dodgy keyboards that worked on my PC and in DOS, but not Windows. Ever since then when ever I get a call about a keyboard typing different letters, my first thought is "Has a Frenchman used your PC?"