This step is sometimes necessary when the Remote Desktop ActiveX Control is
disabled by a Microsoft Update, or by some other method. The instructions below
will guide you through the process of enabling the disabled control.
1. With Internet Explorer open, go to the Tools menu and do the following
depending on which version of Internet Explorer you're using.
Internet Explorer 6 - Click the Tools menu and then click
Manage Add-ons...

Internet Explorer 7 - Click the Tools menu, Manage Add-ons,
and then click Enable or Disable Add-ons...
2.1 On the Manage Add-ons screen, make sure that the option "Add-ons that have
been used by Internet Explorer" is selected in the dropdown as shown in the
illustration below and labeled by the number 1.
2.2 Click on the "Microsoft RDP Client Control" or "Microsoft Terminal Services
Client Control" as indicated by the number 2 in the illustration below.
2.3 Now click on the option "Enable" as indicated by the number 3 in the
illustration below.
Now click OK and then restart Internet Explorer. This should complete enabling
the Microsoft Remote Desktop control.