I hit the wrong key on the keyboard, and the screen downsized using "Explorer"..but when

I switch the browser to Google browser, the screen is the normal size again......Is there something I can co to get the Explorer browser back to full size?...
..The key that I hit by mistake was a key on the typing pad ...titled "Ctrl" ....l It is to the far left at the very bottom of the typing pad.. (is that what the typing thing is called? a pad? or what?) ( You type on this thing, and what is its name?)

I don't know much about this, but any help of any kind would be grateful. Yes, I can continue to use both of the browsers at different times..but I would like to get a full size picture back on Explorer.

Any help on this would be appreciated. And yes, I realize there are far worse computer issues than this one, but, maybe I can get back to full size on the Explorer browser. And I did turn off the computer, and disconnected the plug, ( so there was no electricity entering the system, but that did not work.)