Worksheet opens twice

I have a worksheet created in Excel 97 which opens twice everytime I open it. It happens all at once and unless you pay attention to the title bar with ends with :2 you won't notice it is open twice. It also shows twice if I look under the window menu. If I close the :2 copy the other stays open. This document is used over a network at the same thing happens on every pc so I belive the doccumant is the problem.

Thanks