Also not a fail-safe method, but you can set up a folder with only you with permissions to access it & no other admins. You do that via control panel ... admin something ... can't remember but if you want instructions I'll check it up for you. I have discussed similar descriptions before on the forums.

I can't remember whether they'd be able to see such a folder. Possibly not if it's in your user account area. If they could, then make that folder "hidden" & use a shortcut to your account's start menu items.