What do you mean by double strike? In any case,
it sounds like you have one of those special MS
keyboard drivers (French, UK, International, etc.)
that take advantage of ' ^ ` etc. First thing I would
make sure is that you have selected U.S. English
or whatever it is called.
Sudden new problem: lower-case key 40 produces double strike when followed by
another character (e.g. "she's" or "they'd"), but not when followed by a
space. Tests reveal that lower-case key 1 (`) and upper-case key 7 (^) do
the same thing, but other keys do not.