Currently, VS fails to launch after Vista build to build upgrades. A message box is displayed that says:
"The application has failed to start because its side-by-side configuration is incorrect"
This is caused because the upgrade does not yet handle the migration of the C Runtime Components Side-by-side configuration files. There are two workarounds that I know of for this:

1. You can repair VS in its entirety
2. You can re-install the VC Runtime Components.

Just installing the VCRedist is by far faster than doing a full repair so it is the preferred workaround.

If someone knows where a public link to the VCRedist is, it would be helpful for to be able to point people to it from this post. Internally, feel free to contact me if you do not already know where to find it.