Sometimes a simple restart is all you need, to delete virtual memory swap files. Checking the drive (I prefer fsck) is a good second step. It depends on the symptoms.
It was far beyond a restart. 🙂 I was just starting to have apps randomly quit or act strangely, and the system itself was slowing way down. I really couldn't mess around with it either. I have to edit a short film in a day this weekend and "It's not done because my computer freaked out" won't cut it. I don't have the luxury of troubleshooting software at the moment. Whatever it was, it's gone. It's running like the beast that it is. 🙂