Bought Sims 3 but the game won't launch (0xc00007b) !

@Avareee  Sorry for the late reply; I wanted to get a second opinion before posting more suggestions.  And no, I wouldn't use a tool like the one you linked.  I don't know for a fact that it's unsafe, but it may well be, and there are much more reliable ways to repair your system.

To start with, download Malwarebytes (the free version is fine):

https://www.malwarebytes.com/mwb-download

Open it, click Scan > Custom Scan > Configure Scan, check all the boxes both for scans and for your C drive (and any other if you happen to have an external plugged in), and let it do its job.  This will probably take at least an hour, so you may want to set it to run while you're doing something else.  Let me know what it finds.

If you want to make sure Windows itself is intact, a repair install is the best approach.  It only requires as much time as it takes to download a Windows 10 ISO and to reinstall Windows.  To be clear, I'm not saying you need to do this now, just that it's not too complicated if you want to.  Here's a good tutorial:

https://www.tenforums.com/tutorials/16397-repair-install-windows-10-place-upgrade.html

You'll be able to keep your existing user data and programs, but it's still a good idea to back up anything critical first.  If you do not see the option to keep personal files as shown in step 13, back out and try again.

If you don't want to run a repair install, at least check for Windows updates: hit Windows key-i, select Update & Security, and click the box to check for updates.  If anything installs, restart when it's done.

Either way, please uninstall Sims 3 and Origin as described before (using Revo).  However, when clearing Origin's cache, open the LocalContent folder and delete the Sims 3 folder inside, despite the article's instructions saying to leave that folder alone.  After uninstalling, feel free to do a pass with CCleaner, but you should only need to do the one; it can be counterproductive to keep letting it search for more files to delete.

With Sims 3 and Origin uninstalled, deactivate .NET Framework 3.5: hit Windows key-R, enter appwiz.cpl, click "Turn Windows features on or off," uncheck the box next to .NET 3.5, and restart once it's uninstalled.  Then repeat the process to reinstall .NET 3.5.  Even if you've done this before, please do it again after all of the above.

Reinstall Origin using the full installer linked before, and run it as an admin from now on.  Install Sims 3 on your internal drive and run it as an admin as well, which you can do from its shortcut or from TS3.exe within the game's program files.