Me again!

Nobody seems to be nterested in my little old query but
as it's driving me nuts I decided to post again and hope
someone bites!

Here it is:

Can anyone explain the relationship between Header
margins and page margins?

I would like to use as much of an A4 page for printing as
I can. So I changed the top and bottom page margins to 2
cm & reduced the header & Footer from 1.97 cm to 1 cm.

The result is that the bottom margins now appear to be 5
cm wide thereby defeating the object of messing with the
margins.

What am I doing wrong?
I know SOMEBODY out there can help!!!!!!!!!

Thanks
Jackie D
..