I am trying to make a new movie with Sony Vegas. I used the startmovie command in Counter Strike Source and it made a Avi but when i put it in its extremely jerky and i need to know how to make it not that jerky. Someone has told me that Virtual Dub can do this .. Anyone know how

I don't understand what you mean, by "when you put it in, it is jerky". If you have an avi file, are you then opening it up in vegas movie studio? And when you attempt to play it, it is jerky on your computer? What are your computer specs........

ok i play Counter Strike Source and i play my demo and put in console startmovie <name> avi and it brings up the codec and i chose one. Once i have done that it puts it into a avi file and i move that to vegas but when i play it while in vegas its jerky ... my computer is 2 gig Ram, 500 gig Hard drive, with dual SLI Nvidia 7950's and a 3.0 p4 processor

Please read up on video capturing..
Problem number 1, is that everything you read about video capturing, tells you that you should not be doing anything resource intensive while capturing (gaming is pretty resource intensive). Problem number 2, is that for video capturing, it is highly recommended that you have 2 seperate (physical) HD's. One which runs your software, and one for storage/capture.

There are some specialized programs which are recommended by users, for capturing gaming. I don't keep up with those, but you can find info about them at www.videohelp.com.

You didn't say how much memory you have, but based upon you having other decent specs, I'm guessing it is 2gb or more. (Good idea if gaming and capturing at same time). You really should have a seperate HD for files/capture, if you intend on doing much of it...