Themes aren't working?

[Jessec]

So someone in my family just got a new computer, and all of the installed themes change the window borders/task bar, but mine doesn't. If I click on any theme other than and Aero theme then it reverts to the classic window border/task bar. Any help is appreciated. Thanks.

EDIT: I don't think I was completely clear, it will work on any premade Aero theme, but the "Installed Themes" don't work. The Aero troubleshooter says that the Desktop window manager is not running.

 

[Jessec]

Still no reply! Help please!

 

[Bongo]

Welcome to the Seven Forums
When you say "Installed Themes" are these third party custom themes?
If so you will need to do 1 of these 2 ways of Enabling custom themes for it to work.
http://www.sevenforums.com/tutorials/34579-enabling-custom-themes-windows-7-a.html
Or
http://www.sevenforums.com/tutorials/28377-theme-how-apply-custom-themes.html?filter
Jerry