How do you fix the screen resolution?

I have an LG monitor and the other day one of my friends changed the screen resolution so the writing and everything was very small. I didn't like it this way and so tried to change it back through the control panel. However, i clicked on some kind of screen thinking it was mine and it is now only showing my background and no icons. I turned it off hoping it would go back to normal but am now left with a blank black screen when it's on and nothing else. Any ideas on what i an do?How do you fix the screen resolution?
first of all right click on ur desktop and then select properties then go to desktop tab and then select wallpaper..and apply ok



u will get that wallpaper



to get icons:-

right click on desktop and then select ';arrange icons by'; and in the menu select show desktop icons...u will get the icons...



for resolution



right click on desktop then select properties and then go to settings tab and then under screen resolution with the button select the screen resolution by moving it left or right..select 800*600 or 1024*768 or whtever suits u..gud luck