Download and try the suggested path (from Warez Monster) in gpedit.msc:
Go to:
start / run / type gpedit.msc / user configuration / administrative templates / control panel / prohibit access to the control panel / click it and see if it is enabled.
check the following locations in the registry.
HKEY_LOCAL_MACHINE\SOFTWARE\Policies
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies
you should be able to look through them and find any references to prohibit control. On a normal machine they don't exist, so delete all of them and you should be fine.
Good luck.
ps...
Check in Current user too...
HKEY_CURRENT_USER\Software\Policies
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies