Is It Possible To Reset My Mac?

I've aculated a lot of crap on my macbook (third party apps and a medley of preferences). None of my video editing software is working anymore, including imovie. I think it might be some changed settings or something. Point is this: Is it possible to put all my things on an external hard drive, then reboot my mac as if it came straight from the factory, then just drag the applications and files I want back onto my disk. Or would there be complications?