I run Sony Vegas 4.0 on a Windows XP computer and it works great, I haven’t had 1 crash. Sony Vegas 4.0 came out years ago, I suggest you upgrade if you are using it now and go with 10.0. All of the newer versions of Sony Vegas Pro allow you to use almost any video format and you can convert it right in Sony Vegas plus it allows editing of High Definition videos, which is what everything is going to right now. They even have presets that will have your video perfect for Youtube Viewing.
Overall I am extremely happy with my purchase of Sony Vegas 4.0. It was the start of my video production career and will continue to power my videos. With all of the options and effects that you have on hand with Sony Vegas you will never run out of creative ideas to use when editing a video no matter what style the video is. Sony Vegas outshines its competitors and offeres top notch support to all of its users. Sony Vegas 4.0 will not let you down.