I had a bizarre situation the other week here at work. Acrobat was hanging partway through a document export on a user's PC. As it progressed through the document - and it was over 200 pages, too - the fan on the CPU could be heard to get louder and louder. By the time it reached it's hang point, the fan was going full-bore. And it stayed that way until the Acrobat process was killed.
(And the problem? Acrobat needs the screen at 1024x768 or higher. Don't know why except that at 800x600, it hangs partway through. Always the same spot, too.)
Wade.