Re: Launcher won't come up, taskbar icon disappears.
@burcincokokrem Please move your entire Sims 3 folder out of Documents\Electronic Arts and onto your desktop. When you open the launcher, if it opens at all, a clean folder will spawn with no content. If you still can't play, please take a screenshot of this new folder; I'd like to see whether the typical files are all present. And of course let me know if no new Sims 3 folder appears at all.
Additionally, as a test, try launching Sims 3 without Steam and without the launcher. You can do this by double-clicking TS3W.exe (with the W), which is inside the game's program files. Unless you changed the install location, the full file path will be:
Program Files (x86)\Steam\steamapps\common\The Sims 3\Game\Bin
If this doesn't work either, please run a dxdiag and attach it to a post.
https://help.ea.com/en-us/help/pc/how-to-gather-dxdiag-information/