WS> I took my keyboard apart and inspected that thin sheet
WS> as that is the only other thing I could think to do and I
WS> see what appear to be thin tears in the sheet.

Sounds like the keyboard is history, and once they start to go then
all sorts of strange characters can be produced as the electronics
inside the keyboard tries to make sense of the garbled signals it's
getting.

At least keyboard aren't that expensive now, unless you go for a real
flash type - and they fail just as much as the cheap ones !!