Replying to Vegas 7 rendering problem

ok so i have everything together and edited for my edit and whenever i try to render the video, vegas stops working and crashes. the video is like 3 and a half minutes long. it works fine for other stuff because i did a couple test vids for quality and i didnt have any problems. lemme kno if anyone has had a similiar problem or if you kno what im doing wrong. thanks

sparknotes: vegas freezes and crashes everytime i try to render my edit