When ever i try to open a map file that is in .rar it dosn't work because my comp dosn't know how to open it? Do you need to buy a program? Is there a free program you need to download?

Google for WinRAR.

thanks! at first I thought you had to buy it, but nvm about that

It will bug you to register and/or pay for it in about 30 days, but you can safely ignore that.

I use 7-zip which never bugs me for anything.

Yeah it bugs you , but soon after it stops, lol, poor guy who made it.