Snow Leopard won't let me change desk top

I want to change away from Aurora & translucent menu bar to Aqua Blue with nontranslucent menu bar.

Although I choose those options in the system Preferences box, the desktop does not change. When I go back to Preferences, translucent menu is selected again.

Same problem [user choices not empowered] with the screensaver.

OS 10.6.8 om a dual core mac mini 3.1

Start with a restart.

Try deleting the file
~/Library/Preferences/com.apple.systempreferences.plist

Restarts had not worked to solve the problem, so I deleted the prefs file and restarted, but it did not solvethe problem. I am still stuck with Aurora.

Further ideas? Thanks

So you deleted the plist and then tried making the changes again???
Thats the file that contains the settings. Check the Privileges on that file.

The plist has me allowed to read/write. I deleted the plist then restarted then tried to set the desktop to Aqua Blue but Aurora remains.