I can't rotate or pan but I can zoom I have been having problems with blender recently where I will open a new project and all of a sudden I can rotate or pan. 

I can still zoom and the issue usually just stops after I change views a couple of times, however today I opened a new file and the problem won't go away. 

I am using a 3 button mouse, and these are my user preferences:
After exploring other options with view locking and having no results, I finally found a setting in my User Preferences under the Interface tab called Auto Depth.

Checking this seemed to allow me to pan and rotate again. I am not sure how it got unchecked, but if all else fails, might as well try before performing a reset.

(v2.78a)