See Page Numbers in Word 2007-2013.
Do not work on your document in any way while it resides on a flash drive.

Page numbers inserted in earlier versions of Word were in Frames. You need to find and delete them.

Page numbers are a function of Sections in that they can be reformatted, changed, and restarted at a section break.

Page numbers are almost always in the header or footer even if they appear in margins far removed from the header or footer area.

I hope this helps.