It's been a while since I've played with Windows systems, but issues like this one used to be caused by having multiple keyboard layouts installed on your system. Apart from the language setting (which obviously controls the language of the interface) there is also a keyboard language setting and if you have more than one installed, you can switch between them by hitting a key combination. People may inadvertantly use this key combination and end up with a misconfigured keyboard. My solution was to go into the 'language' settings and remove all but the correct keyboard language. If you want, you can do the same for the interface language.
This used to work this way up until Windows 7, where my knowledge ends, but it wouldn't surprise me if it was still present in the current incarnation of the OS.
Windows 95 from floppy disks? I may still have the disks with Windows for Workgroups 3.11 somewhere, the question is if I've got MS-DOS 6.22 as well....