PDF file more than triple the size of original file

After being a long time Win XP user, I got a new laptop with Win 7.  The first time I ran PDF Creator it wouldn't work until I changed the settings to run as administrator.  It wouldn't work a second time no matter what changes I made, so I had to uninstall, reboot and reinstall today.  So far it has worked.

What brings me here now is a strange problem: I am using PDF Creator to "print" a document from Word Starter 2010 into a PDF file. 

The Word file I converted yesterday was 21.3 megs, and the resulting PDF file was 3.1 megs.  Great.

After the reinstall today I just ran another print, and the opposite is happening.  My source Word file is only 2.84 megs, but my finished PDF file is 8.92 megs!!  Why would this happen?  There have been no changes to the file that weren't saved, or anything like that.  It was a straight "save" then "print to PDF Creator".

Any tips to get this to stop happening?