I may have had a similar problem with my Etrex Venture CX. My GPS worked fine using firmware 2.6, so being the trusting person that I am...I downloaded the newest v2.7 . When I went caching, picked a waypoint and "GOTO"...the menu was locked, could not cycle through all my views, namely the compass screen. I reverted back to v2.6 and I'm back in business, no big deal since I never had any problems before. One final important notice before you do this.....back up all your waypoints using something like EasyGPS or similar software. I LOST ALL MY WAYPOINTS WHEN I REVERTED ! Oh well, at least it works now. Hope this helps.
Hawk_Eyes0608