If you’ve recently upgraded Microsoft Server 2008 R2 and found that RDP has suddenly stopped working, you may want to check out security patch KB2667402. Apparently, if you’ve already installed this security patch, then install service pack 1, RDP will stop working. The fix is to reinstall the security patch after installing service pack 1. Go Microsoft.

Download the security patch: Security Update for Windows Server 2008 R2 x64 Edition (KB2667402)