What is the story on the standard (small blue) USB keyboard? I have suddenly
got two in with one key on each not working and can't find a reference to
this on Google.

Is this a known problem? Is there a simple cure such as unscrew the lower
panel off and run a cleaner over the contacts? Or dip it in a tub or spray
inside with WD-40? Or do none of these 'solutions' work because the problem
is internal and electrical?

Nobody on the Mac hardware forum seemed to know what I thought must be a
reasonalby obvious question

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