I've tried downloading multiple roms all with the .7z extension on separate computers ubuntu and windows and for most files whether it be PsX, Ps2, MAME, or SNES I can't get the archives to extract with 7-zip. I've tried redownloading the same file to see if the file corrupted and letting my computer sit and checking my connection but I can't seem to find the source of the problem. How do I open the archive to get the files to extract?