Just a suggestion, but you're FAR better off rendering out frames as individual JPEG images, then compositing them into a video using something like VirtualDub (free), for the following reasons:
1. If your computer crashes, you haven't lost anything, and you don't have to start from the beginning. Just start rendering again from the last rendered image.
2. You can re-render individual frames if you make adjustments.
3. If you have a long animation, with different scenes, and you only make changes to one scene, why re-render the whole thing when you can just re-render the one scene, or a portion of it?