The best thing to use is PeaZip http://www.peazip.org/ It's completely free and will be able to deal with any archived files. Just right click on it and select PeaZip\Extract Here (in New Folder). The main problem most people will have here is that the .7z file extension is not associated with any program in Windows. Windows 10 should ask you what program to use to open it with and has a tickbox to always associate the program you choose with that extension. Associate it with PeaZip and the icon will change.