With XPSP3, the RDP plugin sometimes gets disabled by an update – there are 2 registry keys to delete which should fix it:

1. Open Regedit and find the following key:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Ext\Settings 2. Within the Settings sub-key, delete the following sub-keys: {4eb89ff4-7f78-4a0f-8b8d-2bf02e94e4b2} {7390f3d8-0439-4c05-91e3-cf5cb290c3d0} Then reboot and try it again.