Sorry to hear, Orla.
After it freezes, does it crash or give an error? Or is it simply non-responsive?
If non-responsive, how long have you left it frozen? Sometimes, a freeze is temporary, and if you wait a few seconds or up to a minute or so, it will unfreeze. (Obviously, we would want to still sort out why it is freezing for that period of time, but knowing whether or not it ever recovers from the freeze will help us to fix the problem.)
Oftentimes, clearing the Dreamweaver cache will help with issues like this. See the instructions here to do so: http://forums.adobe.com/message/2260933#2260933
If that does not help, let us know more about your computer configuration (e.g. what operating system and version, what other software you have installed, etc.) and what exact version of Dreamweaver it is.
It would also be helpful if you could describe the exact sequence of events from the time you attempt to start Dreamweaver to the point at which it freezes, and what you see/what occurs directly before the freeze.
