Here are a couple items that students like to dink with.
This option hides the screen saver page from the display settings control, which stops users having access to change screen saver settings.
Key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System]
Value Name: NoDispScrSavPage
Data Type: REG_DWORD
Data: (0 = disabled, 1 = enabled)
This options disables access to the Passwords icon on the the control panel, therefore stopping users from changing security related settings.
Key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System]
Value Name: NoSecCPL
Data Type: REG_DWORD
Data: (0 = disabled, 1 = enabled)