Some Macintosh Computer Keyboard Keys Fail To Respond.
All Apple keyboards failed and I tried three different ones. This occurred when typing some of the keys on my new iMac keyboard and older keyboards.  For example: 7, 8, 9, (, 0, U, u, I, I, O, o, J, j, K, k, L, l fail to respond!  The solution is to press the keyboard OPTION key 5 times!  Incredible!
