VPN Client problems

Here’s the scenario:

1) Client uses Cisco or SonicWall VPN client to log into network and use Remote Connections.

2) Client’s company is bought by a company that does not use these third party VPN clients.

3) Windows VPN will not work properly, and after removing the third party VPN (Cisco and/or SonicWall), it still won’t work.

4) There are two options we use to fix this… System Restore Point or Wipe the install clean and reinstall OS. Number one is not always possible and number two sucks.

Does anybody out there know of a way to ‘reinstall’ the Windows VPN client in a situation like this?

Thanks!