Deleted Files

Aloha, I logged onto my sims after over a year. My mods needed to be updates, so I downloaded the newest version. When I went to put it in the file, I also noticed that all of the mods had disappeared from files. I added the updated mod, logged back into sims. then an error code about Nisa popped up that is preventing me from playing. I looked up how to delete the mods to have a clean slate, and I ended up completely deleting the entire Sims file, but the mods and error code and download the latest version of my mod message is still popping up. There are 2 things I want to know. how do I get those to message to stop popping up even tho the entire sims file is deleted, and also, how do I regenerate the sims files so that if I can fix the problem, I can create new mods in a new folder. Im new to the whole mods thing. I did everything chatgbt told me to do. Now im left with no sims file, update the lastest version and Nisa error code file.