Maybe then I did something wrong (ex. deleted important file) and nowadays it's a reason for launcher error?
This seems like a strange question to ask us. Shouldn't you know if you deleted any TS3 files? If you did, that's likely the problem.
"I read somewhere that it can be a mistake after uninstalling The Sims 2. I was thinking about it and I remind that a few months, years ago I had problem with TS2. I couldn't uninstall it or something. Maybe then I did something wrong (ex. deleted important file) and nowadays it's a reason for launcher error?"
You mistake our intentions and interest in the Launcher. We do not state that it is possible to play the game without the Launcher. We state that it is imperitive to play the game without the Launcher. That being a primary supposition of the culture here, I suggest that you search elsewhere for Launcher help.
I'm sorry again, english isn't my native language, so I can't understand and write everything I think. I saw that here people know a lot about The Sims 3 so I hoped for help here.