HP Photosmart 8450 problem printing tables

Overall, my 8450 is working *okay* with Vista, except that there's a problem
printing docs that are set up as tables. The print previews always look
perfect, but in one case I was printing a calendar from a pdf and the lines
came out, but no text. In another case, I was printing a monthly menu from
IE7 (again, a calendar) and all the text printed, but no lines. (When I say
lines, I mean the blocks/borders that are in any calendar or table.) I tried
reinstalling the printer driver, but to no avail. The same docs print fine
on a computer running XP. Any help would be much appreciated!!!!!

Tried printing the same docs on an OLD Canon printer (S520) from this
computer and they printed perfectly. My 8450 isn't all that old (at least
two years younger than the Canon!) So, I know they CAN print correctly... I
used the Vista driver for HP Series 8400 printers (it detected and loaded
automatically). I tried deleting the printer, disconnecting and unplugging
it, rebooting the computer and letting Vista reinstall the printer...but it
didn't work. Please help!