Problem installing 7Zip.

7-Zip is the program used to extract 7zip files, therefore being able to have mods for the Sims, but I can't seem to install it. I downloaded it and installed it a few times, but then it's just...not there. As if I never installed it. Help, please? Thanks.

Edit: I managed to extract one RAR file using another program (that only does RAR files). I did all the stuff, then clicked on it. It opened the launcher and I was like, "Oh, finally! Something's gonna work!" Then, it wasn't there to install into the game. -.- Fuck I'm frustrated. PLEASE help!