Why does my internet turn off whenever I try to download firefox?

Every program you use has a tools menu. If you use tools a lot it will be a toolbar across the top of the screen. If you rarely use tools it might be hidden. That means right click at the top left of the screen and it will appear. In Windows you can click "Start" and select "Control Panel" and that gives you a menu of menus to control everything the computer does. You can right click anything and most of the time get a menu for that specific item. For example if you right click the desktop you have the option to rotate the monitor image in some graphic cards. That allows you to have an image that is high instead of wide, by turning your monitor. You don't need to memorize all these things, just be aware that they are in there. Then you can claim to know how to operate a computer at the beginner level.

Find the Tools menu in your browser. Someplace there is a dialog box where you specify the folder to use for downloads. You generally do not run downloads, you save them. There is an icon on your toolbar that indicates when a download is finished and you can click there to run it. If you download a .doc or .pdf or any image type you can run it, but that means your browser will display it. Your browser can not run an executable.