Based on everything you've said so far, I'm guessing that your other
computer has a virus. A virus that has commandeered the association to the
..exe suffix, rendering all .exe's unworkable. Using this information and
your good computer, do a web search at Computer Associates, MacAfee, or
Symantec (listed in alphabetical order, not in order of preference) for
viruses that hijack the .exe suffix. Hopefully, somewhere in your web search
you'll find a solution.
