I used to get a problem like that as well, I don't use FR that much, sometimes when it fails to launch when you press the 'Menu' button, just open up Apps>Utilities>Activity Monitor and check to see if FrontRow has crashed, or is using an unusual amount of RAM (on mine when it crashes it uses about 300megs+).
If it has crashed (not responsing) just click on the stop icon in the Activity Monitor, and force quit it.