Parental Controls On Windows 7
Windows 7 allows the Administrator (You as the parent) to set up accounts for your children with parental controls. You can filter the programs they use, the games they play and even the amount of time they spend on the computer, but what it does not give you the option for is disabling the User Settings. Without this your children can still cause havoc on the computer by opening multiple widgets and using unnecessary themes.
This can be easily solved by going to Group Policy. To do this:
Start button > Search and enter "Group Policy". You then edit the Policy by going to:
User Configuration > Administrative Templates > Control Panel > Personalization
You then select the option from the right and enable the ones you do not want users to employ.
There are other folders there that you can adjust.