When you install the Routing and Remote Access Service Update for Windows NT Server 4.0 \[RRAS\] and/or the Point to Point Tunneling Protocol \[PPTP\], see tip 345, the following registry keys are added or updated. This list may be usefull if an uninstall or reinstall fails:

Registry Keys for RRAS:

                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AsyncMac                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AsyncMac(Number_based_on_bindings)                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\IPFilterDriver                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\IpxPing                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NdisTapi                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NdisWan                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NdisWan(Number_based_on_bindings)                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetBT\Adapters\NdisWan(Number_based_on_bindings)                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NwLnkFlt                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NwLnkFwd                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NwlnkIpx\NetConfig\NdisWan(Number_based_on_bindings)                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasAcd                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasAuto                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasRad                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RemoteAccess                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Router                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tracing                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WanArp                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AsyncMac                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NdisWan                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RAS                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RasAuto                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RasMan                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RemoteAccess                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Router                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Router Phonebook                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkCards\(Number_based_on_bindings)                               HKEY_CURRENT_USER\Software\Microsoft\RAS Autodial                               HKEY_CURRENT_USER\Software\Microsoft\RAS Monitor                               HKEY_CURRENT_USER\Software\Microsoft\RAS Phonebook                               HKEY_CURRENT_USER\Software\Microsoft\Router                               HKEY_CURRENT_USER\Software\Microsoft\Routing and RAS Admin
Registry Keys for PPTP:
                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NdisWan(Number_based_on_bindings)                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetBT\Adapters\NdisWan(Number_based_on_bindings)                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RASPPTPE                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RASPPTPF                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RASPPTPM                               HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RASPPTPM(Number_based_on_bindings)                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RAS\TAPI DEVICES\RASPPTPM                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RASPPTP                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RASPPTPE                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RASPPTPM                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\TAPI DEVICES\RASPPTPM                               HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkCards\(Number_based_on_bindings)