Recently I had to reset my Alienware M17x R3 by re-installing  windows 7 from the disc that came with the laptop. Since then whenever I try change my desktop theme I completely lose the Alienware Theme, the look of the icons, taskbar, etc. The only way I can get it back is with a system restore to a previous date. Any advice? 

Also on a side note my computer says there is 2 different Windows 7 operating systems installed on my computer, which they both boot the same, but could this be a cause or how do you remove one of the two?

Thanks for any and all help