Use google, I got many german sides, where you get Winrar free. Im sure you find other sides too.

I used "Winrar free download" for searching

Be careful that's where malware and other problems will hide....inside the program or zipped file.
If your computer was recently cleaned, the program was removed as it was probably infected. It is not a program I can recommend but there is not one I can really recommend for you at this time. Sorry.

I have used RAR File Open Knife-Free Opener (Google it) for a long, long time and it serves me well. It is free and easy to use if you are looking for an opener of RAR files.

Carolyn a few weeks ago I had problems as I had dl a unzipping programme. I got a lot more than the unzipping programme and it took a while to sort out and remove the problems caused. If in doubt PM rescuer as her knowledge is vv good and the advice she gives is well worth following

7-zip is free and will extract zip and rar archives .. get it from 7zip.com

Noah, You might want to try the official site at WinRaR.com They say the download is 100% free. I did a Google search and there are many options. Are you near any Best Buy stores. You should be able to get help from their "Geek Squad" department. Here are a few links:
WinRar.Download-Insider.com winrar.download-free-soft.net/Free‎
I hope you get some assistance from one of these. If not