Taskbar apps flash but don't open?

Computer woken up from sleep, go to task bar to open an app, get flashes of app when selecting app's icon on taskbar, but app doesn't open. However, some apps open and some apps don't. Those that do open, when left clicked on for a menu item, the app closes. Although an app opens it is not functional. The only way to restore normalcy is to hard close the computer and reboot, then everything is OK.

Thee was disagreement on whether or not a FF uninstall/reinstall would do anything good, so I opted not to.

Some apps do open and work (Windows Explorer and Thunderbird eg) and others open and don't work (Process Explorer, eg). My Norton 360 virus check was negative.