
The first thing you are going to need to do is download yourself and install Media Center Studio which you can get here: Download Media Center Studio
Once installed Launch MCS
To install a theme (see below for theme downloads):
1. Click on the 'Themes' tab
2. Click 'Import Theme' a window will open, locate the .mct file and click open and highlight it in the right like the image above.
3. Click Apply - You will see the progress of the the applying.
When complete open Windows media center and enjoy your new theme.
If for whatever reason you find that you WMC becomes corrupt because of the installed theme you can always restore it back to is original state.
1. Click the 'Home' tab
2. Click 'Restore Default'
And that's it. Back to being like a brand new-second hand one :)
Have a play around, add your own images, fonts whatever you want. Make WMC how you like it! You can always restore it. Enjoy.
Mobius - Download

Image Source: hack7mc.com
Platform - Download

Image source: hack7mc.com
Homeworld - Download
THEMES
Image Source: hack7mc.com
Image source: hack7mc.com
Homeworld - Download