I am having a similar problem.  I was trying to install a new piece of software (Journeyx Timesheet), and after the installation and upon rebooting, the following entries appear in my SQL Server Log:

Failed to Initialize COM (CoInitializeEx returned 80010106)

Heterogeneous Queries and Remote RPC will be disabled.

Using 'xpstar.dll' version '2000.80.760' to execute extended stored procedure 'sp_MSgetversion'.

And at this point, certain functions have stopped working.  For example,

SELECT * FROM ::fn_helpcollations()

returns the following error message:

Server: Msg 7404, Level 16, State 2, Procedure fn_helpcollations, Line 9

The server could not load DCOM.

Likewise, attempting to add a new database prompts with "The server could not load DCOM" (which I suspect is because the New Database dialog box also displays the list of Collations in a drop-down box).

Prior logs do not show this error, and uninstalling the software and rebooting has not cleared up the problem.

Anyone have any ideas?