[Crash] at the start of every game & Legacy [Client] not working

[Crash] The new client works fine and I don't have any issues in champ select, but once the game loads I have a big issue. Basically, the game will start and I'll have about 5 seconds of normal functionality, then my computer freezes. My computer becomes completely unresponsive and the only way out is to shut down my computer. Once I restart my computer, I can reload the game and sometimes it will work after that point. However, recently I've tested custom games by myself and ran into the same issue, but without ANY success. It crashes EVERY time now. There is no error code or anything that pops up. Also, sometimes after I restart my computer and load the login screen, the terms and conditions will pop up for me to accept and I have to re-enter my username despite having the 'remember me' box checked. Now, it is literally impossible for me to play, despite the game working flawlessly just a few days ago (even with the new client).

I have also tried to repair the files multiple times, but to no avail. [Client] After experiencing the crashing enough times, I tried opening the Legacy Client to see if it would make any difference. However, when I click the button to launch the legacy client, the window closes out and nothing else pops up. If I try opening the new client again, it opens as if I had just closed out of the other window (meaning, there wouldn't be a pop-up saying 'another instance of LoL is running' like it used to).

Any help is appreciated so I can play again, thanks!