WASD <> arrow keys not responding in-game

So my little sis uses my pc to play Sims 4. She recently tried to update the game to the latest patch and she immediately ran into a weird issue. As her big sis, who doesn't really play the game but is a little bit more tech savvy and her real life pc support, she came running to me with her issue and I've been trying to get it fixed for the last 2 days, but with no luck..... 

The issue is: our keyboard suddenly stopped responding with certain keys in-game. Arrow keys, WASD and <> keys don't respond at all. I've been looking through all the great wide web to fix the issue but there's little info about it. 

What I've tried so far: 

Fresh new game
repair the game
remove ALL doc files (backup somewhere else). 
Reinstalled the game
Checked for hardware updates. 
Unplugged the keyboard and plugged back in different USB ports. 
Many times I rebooted the game and/or pc.
Uninstalled all DLC she had up to base game only to see if that was the issue. 

Nothing changed....

While browsing for help I stumbled upon the Default.ini file in the game installation folder. I saw that there was a section with [GameplayKeys] which was empty. Nothing in there. Maybe something's missing? 

Any other suggestions? 

gameversion = 1.75.125.1030
no cc or scripts.