I believe the smart card credentials are only required if you are using WPA2 Enterprize setting for the wireless network security. Also make sure you aren't using WPA2 Enterprize setting in your routers control panel.
You shoud also check the wireless security on the Vista and Windows 7 machine and make sure it's set to use WPA2 PSK [AES] only not WPA2 Enterprize under Network and sharing center > "Manage wireless networks"
It also shows your PC as being in a Domain which might be part of the problem.
After reading more about this problem apparently Vista has problems working with WEP security on certain types of routers. If you aren't already using WPA2 PSK [AES] you should try using it instead of WEP.