Mac Computer Screen Size Adjustment?

I accidentally did something to my Mac computer to change the screen size, and don't know what I did. The problem is that the screen size is too large to see all at once. I have to move the mouse around to see the sides and top or bottom of the screen. This means I cannot see the dock without moving the mouse down, and I can't see the top bar. Any ideas on how to fix it will be appreciated. ThanksMac Computer Screen Size Adjustment?
Sounds like you tuned on Zoom (found in ';Universal Access'; in System Preference). Just press Opt-Cmd and the hyphen. That will turn it off.



To make this less of a problem next time, go to Universal Access in System Preferences and click the ';Options...'; button next to Zoom, then move the maximum slider all the way to the left.