Can someone help me with this? I've been trying to download the sims2pack Clean Installer (no install) version into my laptop, because I accidentally deleted the folder and didn't uninstall it properly. So I tried the no Install version, and it was going well until I try to set the "Open this file with this program always" but when I try to, nothing happens, it shows me the deleted sims2pack clean installer. It does not change to the no install version. What do I do?

You probably need to uninstall the original Clean Installer properly first.

You can just select the exe of the no install version manually in file associations. You don't have to pick from actually installed programs.