I had a similar problem... upon stopping I might lock up (reboot), but usually mine was when shutting off the engine.. only in GV's.
To make a long story short, it ended up being sound driver issues. I use USB Surround headphones, and apparently they made an old and new version of them (both look nearly identical). The CD that came with mine had drivers for the new version, which loaded and worked fine, but weren't right.
After I dug around on their website for hours, I ended up finding the old version drivers (was buried in an dark FTP cave on their site).. loaded them and have not had those problems since.