I will explain the assets. I have a folder for projects and in that folder I have more folders for each individual project. In these individual folders I have some m-peg, some lower-thirds in .mov format some stills and some music. These are the assets. If you move these (without moving the .veg file) Vegas will ask you where each file you used in the project is. (Because it can no longer find them.) If you respond to the dialog for each file one at a time, you may be able to isolate the problem because Vegas will stop responding on a certain file. Replace that file and you may have a working project. If it fails on all files of a certain type then you may have a codec issue.
I hope this helps you recover your work.
Jeff
http://www.narrowroadmedia.com