Adobe Flash Player used to be the web's top technology for animations, games, and even simple things like menus and buttons. But in recent years it has been completely disabled, even by Adobe themselves, making it very difficult to access some of the classic content that was created with it. There are years of web games, including some of my favorites like the Papa's restaurant games, which are completely inaccessible due to the fact that you cannot use the player through normal means, and the emulators that are currently in development still do not support all the features that are needed to play most later Flash games.
Also, sites like my Flash Game Archive (although I don't entirely maintain it anymore) and any other game site which still has flash files, depend on Flash Player, or whatever emulator can be provided, being able to properly run the files. So, here is how to get Flash Player working if you are in need like many others!
Make sure that Adobe Flash Player is installed, working and enabled in your browser. This is a bit of a tricky one nowadays as Flash Player has been disabled by most modern browsers, and the newer versions of Flash Player have a killswitch that makes it so you actually cannot play a single thing anymore. I'll help you fix this!
Before you install the old version of Flash Player below, you MUST make sure you have completely uninstalled any other versions of Flash Player from your computer. Follow this Windows guide or the Mac OS guide on Adobe's website to do that.
Alright, now you need to install a specific version of Flash Player, version 18.104.22.1681, which is the latest version of Flash Player that does not contain the killswitch. I've got the Windows download, the Mac OS download, and the Linux download right here for you.
Now that you have the right version of Flash Player installed, you need to install and use a browser that still supports Flash Player. That is, even if you install the correct version of Flash Player, you will still be unable to play Flash Player games if you are using a modern browser that has disabled it for security reasons. Google Chrome is a good example of this. I recommend Waterfox or Waterfox Classic, a fork of Firefox 56 that still supports Flash Player with no problems.
And that's it - You should be able to load up any Flash game if you follow the above instructions!