I don't have an answer, but I think I have the same problem in Word 2007.
It's intermittent and affects multiple users: each line in a document prints
superimposed on the first (left-hand) character of the line. The exception
is for text that has direct formatting applied -- italics, bold,
highlighting, etc. That text prints out more or less as it should. But
"normal" text is all squished up at the left margin.
Also, the act of printing causes this distortion to happen on the user's
screen, too -- not just on the printed page.
Usually restarting Word will cause the problem to correct itself for a given
document, but it's still a big nuisance.