I also use CutePDF. Basically it installs as though it's a printer; when you wish to convert your MS Word document to a .pdf, just use 'File','Print' and then select the CutePDF option in your printer list. Doesn't take long - when it's finished just save it to wherever you wish.
But if you use it to create a .pdf version of a MS PowerPoint presentation, the file size could well become pretty big!