Look we all know computers are humming golems waiting to pummel us into demented, techno-utpoian submission. But minding that, you have to find a way to work your way back from the web.
The first step is to take one hand off the keyboard. There actually is a keyboard shortcut to closing what's called a browser window, but let's focus on the more straightforward approach. When you move your hand (or hands) off the keyboard, place one hand gently (do not slap, smash, poke, goose, pinch, swat) on the mouse.
Now--and this part is very important: place one finger on the left mouse button. DO NOT SNAP YOUR FINGERS. When you move the mouse, you will notice something moving simultaneously. The cursor is not mimicking you as in a 19th century dumb show; you indeed control the cursor.
If you look closely, you will notice an x in the top right corner of the screen. Sorry, an "X." Remember how I told you to use your finger to click the left button on the mouse (on top of the mouse not on the side of the mouse [the top has the click wheel on it])? Now gently press the button while the cursor (by now a white arrow) is over the x ("X"--gah I keep doing that) and voila! You have successfully logged off the web.
Now that you are successfully logged of the web, I can lay in my white cotton briefs and listen to the mellifluous G-funk of "Pumps and a Bump."