If you have open the letter you want an addressed label for, Click on the Mailings icon in Word 2007, then Labels, click on the Single Label then choose the position on the page of labels you want to print. i.e. Row 1 Column 1. Equally so, if you just want a label, then bring up a blank document and go through the Mailings/Labels route again and type the address in the label window and pick the particular position of the label you have available in the sheet of labels.
Hope this helps.