Windows Theme Lost after every Restart?!!

I originally lost my windows "luna" themes and it reverted back to classic themes only
at this point it would not let me change the theme without giving me a much dreaded error message for even highlighting the new theme

Now under
rightclickdesktop -> properties -> appearance
I can no longer change the selected theme as the box and drop down is "greyed out" and locked for some reason
However, i can change the color and font and effects and advanced.

Unfortunately, without an external program like Tuneup Utilities 2009 i can not change my theme back to XP's Luna theme from classic any other way of my knowledge. So i have to run that program every time i restart if i want my theme back every time i get on my pc....


Please help??

so 2 situations:
1. greyed out theme selection
2. reverts on start up every restart or shutdown