As Tepid states, GPedit is your best bet, but GPedit is only available for Windows 7 pro and up, and given that this is a 4 yr. olds machine, I'd be surprised if it was running pro. ________________________________________________________________________
Anyway, the problem with GPedit is that you can't selectively apply it (i.e., only to standard accounts).
Child Proof Windows 7 ________________________________________________________________________
The 2 possibilities I can think of off the top of my head:
1) Create an image of his system (Windows Backup, Acronis or similar) that can be reverted to when needed. You would have to create a new image whenever there is an 'authorized' change
2) Find a 3rd party software that will allow you to disable certain aspects of the system.
I remember when kids used to play with toys. I guess I'm getting old...
As for the games, have you tried right clicking on the 'Disney' shortcut and choosing Properties|Compatibility tab, making sure that there is a check mark next to 'Run as Admin'? I think that would work (you can ignore the 'Run in compat mode' option [step 2]...stock screenshot
And as for W.E., he can get to it through the start Menu, via any folder shortcut or simply by pressing winkey+E, amongst other ways.