THERE IS NO GEAR SYMBOL AT THE TOP RIGHT OF MY SCREEN?

Answer 1

Things to try:   

Press Control and 0  (zero) keys at the same time  

to return the screen to default size.   

Also, look for scrollbars, because maybe you are not seeing the whole screen.

To get a better answer,  indicate what program 

you are using or  what you are trying to do?

Also, you could take a screenshot and post it here. 

Answer 2

Is there a 3-horizontal-line icon, or 3-stacked-dots icon.

The icon is meant to represent a list of choices, in other words, a menu.

If you click on it, you may find a choice called "settings" (with or without the gear symbol).