Have you tried turning it off and on again?

Today I was trying to register a Plugin to Dynamics CRM 2011, and I received the following error:

System.Runtime.InteropServices.COMException: Microsoft Dynamics CRM has experienced an error.
 Reference number for administrators or support: #63F08CDB

Using the platform trace, I tracked it down to the following exception:

System.Runtime.InteropServices.COMException (0x800703FA):
Retrieving the COM class factory for component
with CLSID {E5CB7A31-7512-11D2-89CE-0080C792E5D8}
failed due to the following error: 
800703fa Illegal operation attempted on a 
registry key that has been marked for deletion.

From further digging, this turned out to be an issue to do with the installer having deleted a COM registration, but the registry hive not yet unloaded due to user locking it. To fix, I simply re-booted. Just goes to show you - as that great philosopher Roy Trennaman once said
'Hello, IT, have you tried turning it off and on again?'