How to get the up and down scrolling arrows back on my PC?

Right now, I have the scrolling bar, used to move up and down on a website page, but for some reason the up and down arrows have disappeared.

This morning when I went to look at my computer (a Dell laptop) I noticed that I was not connected to the internet. When I clicked on the little icon that looks like bars, that shows you how much of a connection you have, it said that there were not connections available.

I re-started my computer, but that didn’t help. Then I reset the modum and clicked on the icon again. It said to push the button on my computer that provides wifi access (the icon with the little A-shaped electric tower, F2) and that solved the internet connection problem. Unfortunately, when I re-started the computer, it left me with no up and down scroll buttons.

Did I accidentally delete them? How do I get them back?

Thanks to all of you computer whizzes, in advance : )