What version of MS word do you have?  I assume 2007 if you have Vista, but if not let me know (these directions may also work for earlier versions).  Click on start/all programs/Microsoft Office/Microsoft Office Tools/Microsoft Office Diagnostics.  Then run the diagnostics test.  This may resolve the issue.  

My MS Office programs crash when I have my default printer set as my HP.  Others have had a similar problem, so if you have an HP printer this could be the cause.  

What are your event logs saying?   

I have Microsoft 2007. The diagnostics test didn't seem to fix anything. It said one problem was found and corrected but word still wasn't responding after the test. I have a Canon printer not HP so I don't think that is the problem. The event log lists about 20 office sessions that were terminated unexpectedly, or ended with a hang, and one session that ended with a crash. The first time it occured was in the middle of May so those are all the times I've tried it since.  

May be an add on hold down control while opening word and this will open word in safe mode.

Then go to the office button on the top left and then to word options on bottom left of menu.

Then go to addins then to manage (bottom left)

then select COMs and then click go 

Disable all add ins (my bluetooth add in made word take 5 seconds to load instead of 2) so naturally was diabled. Don't need most of the add ins for word.

I have done the same thing, my MS Word still freezes