You mean it stopped working on your current project or just stopped working totally?

If it's just that project, my best advice would be to start over. Since you yourself said "I'm not sure if I did something with Cache settings or something like that" then I'm not sure if there's anything anyone can do to help you.

Try deleting Maya's preferences folder to see if that resets it. Go to Start Menu > My Documents > (User if there is more than one user) > Maya > 2008(9) and then delete the Prefs folder. The next time you start Maya, it will ask to use old preferences or create new ones. Create new ones. See if that fixes it.