The photos and menu items are highlighted, but I cannot click them.
Application is not frozen, as well as OS. I still can use keyboard and shortcuts.
With the rest of the OS and apps no problems whatsoever.
Restarting LR and resetting preferences doesn't not help.
Win 8.1, LR classic CC of the latest version.
I am using a ASUS laptop with GeForce 840M on board with the latest drivers available for it.
Sorry that you cannot use Lightroom Classic CC as you cannot click on the Photos and menu within the application.
Could you please uncheck the option "use graphics processor" under the Preferences> Performance menu in Lightroom?
If that doesn't help, optimize the Lightroom catalog from the File> Optimize catalog menu and let us know if that helps.