See http://support.microsoft.com/?kbid=839371 "Margin marks or
crop marks appear on each corner of the page when you open a
document in Word 2002 or in Word 2003".

EWilke wrote:

Each time a document displays there are two connected grey lines forming half
a box in each corner of the page. I have had this problem one other time and
the only fix I could come up with was a system restore, however this time it
did not work. I have tried uninstalling/reinstalling my software but the
problem remains. I need to use my MS Word and must get this off the system,
whatever it is. Thanks!