My mouse cannot left-click on anything. Cannnot open a or close a document by left clicking. It will open or close via pull-down menus and right-clicking. It also cannot select anything or drag anything. I have used several mice, no change. It all works okay when I safe-boot (restart holding down the shift key) but after regular start-up, it doesn't work anymore. Is this a virus?
Problem solved thanks to Eric Cote:
"you may want to trash your preference files under:
Users/<your user name>/Library/Preferences/com.apple.driver.AppleHIDMouse.plist
then reset the mouse prefs"
Thank you Eric!