Well this shouldn't take that long, and I am assuming you haven't done highly sophisticated compositing with many effects. In addition to the above, if FC asks you to render, this means that it can't play in real time without "baking" your effects with the footage first. Something you may also want to check in general, I would first close any unnecessary applications that are open, I would render only a saved project, I'd check my memory preferences allocated to FC in my user/system preferences, including cache. Other things that I normally do as a maintentance beyond the applications is to run disk utility to repair permission, zapp my RAM occasionally (this is only me), run maintenance scripts and check that I am using all the SW updates for the apps that I am using. That sounds like a lot but maybe FC is having a bit of difficulty with something litte but causing the headache. Try the above and good luck. Save any work you have done before though. Looks like you solved the problem anyway.