Windows Media Connect Setup Failure

When I go to www.xbox.com/pcsetup and run the setup program for Windows
Media Connect, it downloads, briefly appears to extract some files and
then disappears, never to be seen again. The blue screen which is
supposed to appear never comes up. I have installed this program
successfully using my housemates notebook on the same network.

I am wondering if this has anything to do with me downloading and
installing (successfully) the Windows Media Connect application from
the Microsoft website. It would not recognise my Xbox and I realised I
should probably use the Xbox specific application on the Xbox website -
but it won't work.

Is it possible there are some files, processes or registry information
that are having this affect?

Thanks,
Aaron