Problem with .avi files

[Cucuzza]

Look i enjoy making cod movies, but ever since ive reformatted i've been having trouble with avi files. Yes i do have divx and xvid. But every time i open a divx or xvid video its very choppy and it skips. Also when i render a video with virtual dub it comes out very choppy and not like it used to. I think this also has to do with my problems with fraps (since fraps makes recordings .avi files)because every time i try recording with fraps: on full screen it doesnt give me more than 10 fps and on halfscreen it doesnt give me more than 20, and no i do not have the fps locked at this. Plz could somebody tell me what the problem is. I have all my drivers and everything but i just dont get it.

Thank you