Web Remote Workplace Stops Working After Installing IE8

This is a known issue with no immediate resolution other than deleting a registry key.
When attempting to install the ActiveX component for Remote Web Workplace, you'll see this error:

Remote Desktop Web Connection ActiveX control could not be installed. A connection cannot be made without a working installed version of the control. Please contact the server administrator.

The culprit seems to be IE8, but further investigation leads to show how Windows XP SP3 disables the RDP ActiveX Control after installation. Incidentally, this also happens on Windows Small Business Server 2003 after applying SP1.

If you use the "Manage Add-ons" dialog in Internet Explorer to enable the "Terminal Services ActiveX Control", the actual ActiveX control is missing from the list, even if you install the component manually. Its simply not there.
To fix this issue:

1. Navigate the registry to: HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Ext \ Settings
2. Locate {7584c670-2274-4efb-b00b-d6aaba6d3850} and delete it.
3. Close all instances of Internet Explorer and re-run Remote Desktop Web Connection.