To delete any version VAG-COM, all you do is delete the folder. We don't mess with the registry. Can't say what your eBay cable suppliers driver does however.
As to the program stopping, version 409 was never written to run under Vista and is not Vista compatible. If you are not running in XP compatibility mode, the program is not going to run correctly - if at all.
Then, there may be an issue with your cable that causes the program to stop.
All I can say, is that none of these problems ever happened with our interfaces. But then we were not running Vista in those days. Current versions of VCDS are fully Vista and Windows 7 compatible but they require genuine Ross-Tech interfaces.