Windows 7: Very wierd problem with user account/profile and permissions

Hi all, first post here.
I'm having a very strange problem here. Suddenly my main account (which happens to have Administrator right's) seemed to have lost all his permissions. I cannot open my network configuration, cannot open certain sections of control panel (those who require administrative privileges/elevation), and so on. Digging deeper I found this wasn't a privileges problem since I can navigate to c:\windows\system32 and run cmd.exe as administrator (through right click->run as administrator) and then launch explorer as administrator which would "solve" most of the problems. Besides, most (but not all) of my shortcuts just disapeared from my desktop. I have two main causes, one of them being the installation of some aplication (Registrar lite, Registry editor), the other one, which is crazy but not tottally unthinkable, is some sort of wierd security policy that may (or may not?) have been applied through my works network.
Does anyone can think about a way of fixing this issue? I can't even change my wallpaper...
I would be very gratefull for receiveing some help besides Format+Reinstall.