word 2007

attempted to insert a grid line over a jpg picture.
click insert table on ribbon =>
used large number line 80 row and 80 columns on the panel window

the word document page showed the grid line under the image, but also under
all other pages of the word document?

other open minimized document that on the screen task bar, when clicked to open from the window 10 screen task bar, it shows all its pages also has the same grid line on all pages but under the text and pictures.

how to remove the gridlines of table inserted form the word document?
why it cover all other document that open at that time?
how to remove form the one document got inserted into , and other document on the task bar?