This is fixed. I didn't know what was wrong with it. It just wouldn't work. I used the firebug to find the issues. Issues fixed below.
usedLetterBoxes(); //updated from Boxs to Boxes
document.getElementById('wordBoxes').innerHTML = tempText; //changed from Boxs to Boxes
alert ("You're Dead\nThe word was " + word); // update from Your to you're and made word lowercase