I can't get an old world I created to reinstall no matter what I do for some reason. Solved!

Sorry Guys, I spoke too soon. It appeared to install and I thought it was fixed. It, even went into the installed folder and now its not showing up again. I thought it worked and than I went back to play the game today. It didn't work. It still didn't install properly. :( I'm sorry, especially to @puzzlezaddict. I don't know what to do now. Thanks