Print different with identical settings

I am running Excel 2007 on Vista. I set custom margins on my worksheet so that the print preview and actual print on my printer generates a nice single page, centered, etc. I provide a copy of the file to a friend who uses a different computer and printer. She is also using Excel 2007 and Vista. On her computer the exact same file, with the same custom margins settings produces a messed up print preview and actual print. On her setup the farthest column to the right drops off the page and generates a page two. Why would this happen when we are working with the exact same Excel file with the exact same settings in every way?