My current version is the most recent as of 10/24/16: EU4 v1.18.3.0 Prussia (9198)
While I don't believe this to be the cause, I thought I would mention it in case it was possibly the source of the issues but then I wouldn't know why it would be now affecting CK2. I did use mods but it worked 3 times before in the same night. I recently played a multiplayer game with a friend and it glitched out and has stopped working since. I reinstalled it with no success and tried with the previous and current version as of October 24, 2016. They highlight but when I click them, nothing happens. None of the menu buttons, including the ads, links, and any other buttons are able to be pressed. When I finally do get it to launch, and it seems random at times when it wants to work, the start menu buttons cannot be clicked and I'm unsure of the cause. I am running without mods but I previously had them installed but none of them were enabled. The cursor is there and the buttons are highlighted but when I press them, nothing happens. When I enter the launcher, I am sometimes able to press the tabs for mods, and press launch and other times I cannot press any of the buttons. I'm not entirely sure where to post this considering it's happening with both CK2 and EU4 but not for HOI4, EU3, VIC2, etc.