Well it's probably a little late for ctrl-z, but that would have been a good idea from the get-go. I'm not quite sure what's happened, your description is not very good. Try removing all borders (there's a button in the toolbar that lets you select the border style, or you can right click on the cell, select Format, click th borders tab and delete them all... that's from memory as I don't have Excel on this computer, but I know it's something to that effect).