Hi Bob,
No problem

I assumed it was this, but I just wanted to make sure before I started going down this route.
Let's try clearing the cache stored by WMC.
Please download and install CCleaner
and CCEnhancer. The links to both can be found here:
http://www.vistax64.com/software/86472-latest-ccleaner-version-released.html
Install CCleaner first, then install CCEnhancer.
Once you've done this, open CCleaner. Do
not go on the registry tab, this may cause more problems than it solves - all we want is the cleaner. You should see a large list on the left and two tabs at the top:
Windows and
Applications, select the
Applications tab and scroll down to the
Multimedia category. Towards the end of this section, you should see
Windows Media Centre and
Windows Media Centre More*. Tick
both then click on
Run Cleaner. This may take a few minutes to complete. Once it has completed, please reboot and let me know if you're still having the same problem
Tom