I seem to be having a problem with opening Windows Themes as instead of the theme applying as soon as I click on the file, it is opening the 'Desktop Icon Settings' instead (see image). I've never had this problem in the past and have only noticed it since trying to download a new theme today.

I'm downloading the Themes from the Microsoft website and have checked that I am downloading compatible themes. The default app for opening the themes is currently set as 'Windows Shell Common Dll'.

Can anybody help as to suggest what's causing this to happen?

ThanksClick image for larger version. 

Name:	Windows.PNG 
Views:	1 
Size:	50.5 KB 
ID:	114082