The USB ports on my MacBoook Pro13 stop working after a while (new devices aren't recognized by the OS, already plugged in devices don't work any longer, the behavior is the same for all USB devices and both USB ports). Doing a restart fixes the problems for a while (about a day of use). The way I'm usually working, the Mac goes to sleep a few times during the time it works. I've tried the standard procedures of resetting PRAM and repairing disc permissions without success.
I'm not sure how long I've been having this problem, it might be related to updating to Mountain Lion or some version change in VMWare Fusion (and no, the USB hardware is not available there, either). As the problem is not occurring directly after a reboot, I'm assuming it is not Hardware-related. Still I'd like to avoid a complete re-install.
What can I do to further diagnose and fix the problem?
UPDATE: Thanks for the suggestions. I wasn't able to try all of them .. interestingly, my USB has been working for more than a week now, and I'm not sure what changed. (Maybe I'm using VMWare in a different way, maybe it has to do with the way I use my MacBook.) So I haven't been able to verify that any of the changes solve my problem (which makes awarding the bounty a bit tricky). I'll update the question when I have new information - but hopefully my USB continues to work!