Hi there, if you know me from round here you will know i have been asking similar questions recently, to be honest it depends on the amount of RAM you have, processor etc, say you are running on a 4GB, Intel i3/i5 processorr your gonna be able to just run Adobe After Effects, anything under that and it will be slow as hell!
However this kinda sofware is expensive (However you can get cracked versions on the web, not that im recommending you get one, at your own risk,!)
there is also a easy, and quite effective called
Sony Vegas Pro
you may want to find a free one on the web,
if you are only interested in basic word effects, video editing i recommend
Serif MoviePlus x5
it is easy to use and there are plenty of plugins to make it more complex.
However if you are on a budget and are after a movie creator
use windows live movie maker, it is extremely restricting and you cannot do much at all,,,
anyway i hope you have fun !
P.S to find out your pc specs go to r<<run>> type dxdiag> and post it here on this post for us to help you perfectyly!