I assume you're talking about WinRAR? You don't actually need to use that specific program to extract .rar files. 7-Zip works as well. (I just tested this on my machine and it worked.)
You may find 7-Zip to be easier to use and safer looking. It's also totally free and doesn't show a pop-up asking you to buy a license every time you open it. (Although to WinRAR's credit, it is an extremely well-known and reputable program.)