Sims 3 in game screen glitching

@LoveLovciaPL  Yes, you did the dxdiag correctly.  And I see the issue here—your integrated graphics card is quite old, and it was never all that powerful to begin with.  It's possible that the screen flickering is due to the card not being able to handle Sims 3 anymore.  In that case, there wouldn't be much you could do.

However, if the card is still working okay in general, you can try running an fps limiter alongside the game.  For an Intel card, RivaTuner Statistics Server is probably the best option.  While its usual purpose is to bring down high frame rates, it can also help with flickering and other graphics glitches.

The real download is halfway down this page; don't click on any of the ads near the top:

https://www.guru3d.com/files-details/rtss-rivatuner-statistics-server-download.html

When setting up RTSS, use TS3.exe to create a profile for the game, and specify a limit of 60 fps.  Your card won't go that high, but it may still help to have the cap in place.  You can also experiment a bit with the other settings, although the defaults have always worked well for me.

RTSS does need to be running while you play in order for it to work, but it takes up hardly any resources, and you can just minimize it to the tray.

Finally, it's a good idea not to run anything else alongside Sims 3.  Your computer is already working hard enough with the game alone, and trying to multitask is only going to make things harder.