Can't uninstall my old version of Google Talk

In a small number of cases, users who have upgraded to Windows Vista before receiving the latest Google Talk update will be unable to first uninstall the old version of Talk.

This is because the user account doing the Talk update lacks administrative rights. You'll need to ask your system administrator to uninstall the old version of Google Talk, then install the new version from http://www.google.com/talk with your own user account.