wIRELESS KEYBOARD COMMANDS FOR IMAC

I'M NEW TO USING VOICEOVER ON IMAC
BY ACCIDENT, I CHANGED "COMMAND + W" (WHICHCLOSES A WINDOW). NOW IF I PRESS "COMMAND + W" IT OPENS "SEARCH THIS IMAC".
I ALREADY TRIED RESTORING THE KEYBOARD COMMANDS IN SYSTEM , BUT IT DOESN'T WORK; MY COMPUTER DOESN'T DO ANYTHING.
PLEASE PLEASE HELP. I USE "COMMAND + W" A LOT AND I WOULD LIKE TO HAVE MY NORMAL COMMAND RESTORED.
THANK YOU FOR YOUR HELP.