I had the same problem with my 770 when I first started using it. I also couldn't access the "extra" program for changing settings (changing probe to break a circuit on contact or not, etc.) I remember getting an error when I tried opening that program and doing a search on the error and was directed to download an update for XP and a little command prompt stuff and moving the file into the proper place fixed it. I would contact Tormach about this as I don't remember all the specifics but it did work even though Windows gave me an error message as I was doing the updates. Good luck.