Pressed the big red button and a the windows logo showed up

So I have a 40 year old son and I decided to check his computer like other parents do. Usually when I check my son's computer, it just has the normal desktop you're supposed to see on your computer: a white screen that says Gooogle.com or something, whatever the kids do these days. Search history is also empty so I know that my husband doesn't use the internet like a naughty child. But then I accidentally moved the little paperweight on his desk and a pointer moved to the corner of the screen, right above the a red X. I tapped the paperweight, and there was a little button!, I pressed the button, and the screen changed! There's a picture that showed up with so many weird icons, the bottom bar had a thing that seemed like the devil made it to be parent-proof! I don't know what to do please help my son has hid a whole special hacker interface from me to hide his devolution into sin.