I wasted 2 days re-installing everything to fix a “Vegas (pro 10) stopped working” nightmare during a long edit (2 cams 2hrs). I’ll cut to the chase, the first hour edit was non-problematic but then the second half kept crashing. I remembered the un-manned cam stopped after the battery ran out, so I double checked the last clip (AVCHD) and sure enough it was corrupted at the end. When I removed it from the timeline, I never had another crash.
this probably applies to any corrupted highly compressed format like AVCHD that can cause Vegas 10 or 11 to become unstable and bail-out.
Double check your source files before you waste time looking under the hood.