If you are having this printing problem using one of the Office products (like Word or Excel), there is a "print preview" function that allows you to see what your documents will look like, including headers, footers, margins, fonts, page size, etc. Does you printed document look it does with "print preview", or different?
Same with printing from a browser (e.g. IE or Firefox). Again, there is a "print preview" that allows you some control over scaling and landscape/portrait so that you don't lose printed output. Again, if this is the source of your printing problem, does the printed output look like the "print preview", or not?
What kind of printer do you have? Any driver
options for printer setup? Any support software from the printer manufacturer to handle printing problems like you're describing, or maybe fine-tune printer setup?