Since yesterday, my computer has been acting a little weird. Aside from a flash game's framerate decreasing to a pathetic 15-or-so, any notifications that would normally come into view don't come into view. Whenever I get an email, my Windows 10 computer only shows me in the notification button that there is one notification, but I have to click on it for the notifications to show. At first, I could simply click on the little window with my mail on it, and then I can instantly read it, but now I have to take extra steps to do it.

I have the same problem with Discord. Whenever I get notified of a message, I hear the sound, but the message doesn't appear in a window for me to click and go to. I have to click on the notification button, then on the message.

Any way I can fix this? I find it quite a big annoyance to have to pause my game every single time I hear the discord notification sound only to hear it turned out to be for an announcement I have no interest in reading.

Right click the box in the lower right corner (which is what I'm assuming you're talking about) and you should see an option called "Turn on notifications".