Very likely, without having a trawl through Google there is an application in Microsoft Office that in some cases conflicts with Dreamweaver. It is fixed in the latest version but is not offered as a free fix, so it must have been pretty big. Updating Dreamweaver is just too expensive unless you are a web professional.
Have a search around and see if there are things you can take off Office you dont use to make Dreamweaver work.
In my opinion DW is the best editor out there, getting something else would be a backward step.
I also think Open Office is better then the Ms original version, it has all the features and more and best of all it is free.