On Windows 8.1, you usually would end up with a Firefox icon on your Desktop. Firefox is a traditional Desktop application and doesn't integrate with the main Start page. If you're not sure whether Firefox finished installing successfully, you could try using the "Run" dialog. On the lower part of the start screen where you find all the small icons, you usually can find "Run" among the accessories toward the right side. In the Run dialog, type or paste '''firefox.exe''' and click Run or press Enter. Does Firefox start?