Oh... its easy... Just go to this link: http://www.rarlab.com/download.htm and look at the links at the top. For Windows, focus on the two at the top. WinRAR x86 link means the download link for 32 bit computers, and WinRAR x64 is for a 64 bit computer. If you do not know which you are, then go to Start, right click computer, and hit "properties" at the bottom of the list. Then, a screen comes up with the Windows logo. "It should" Then, look under the tab System and where it says System Type: it will tell you. Download WinRAR now. Once its done.. download my thing.. and it should already be associated with WinRAR. If it isnt, then right click on it, do open with, and click on WinRAR Archiver. then you will see a few folders. if you go too far, you will see the level.dat stuff.... if you see that, go back one, by clicking the small arrow to the left. Put that into your saves folder by going to start, and type in the search bar, %appdata%, and go to .minecraft and the saves.. YOURE DONE! NOW YOU CAN OPEN EVERY .RAR or .ZIP with this PROGRAM!