[Patch 7.8] Application error 0xc00000005 when launching game

Hi there, I get the widely known error "0xc00000005 - This application could not start properly" when i try to get into a game AFTER loading the patcher/client. I tried a lot of troubleshooting me myself and even ended up reinstalling Windows which did not seem to help. The only difference to my old system is, that this issue back then troubled various programs and not LoL alone. Now it's (gladly?) LoL-only. As for the trouble-shooting that i tried myself: -deleted "lol_patcher" in the "...\RADS\projects" folder -set the whole LoL folder on C: aswell as the 3 launcher .exe files as exceptions for my Avast -[on old system] deleted Avast and switched to AVG (which i personally don't like at all) which seemed to help for a while -disabled Avast for 10min right before game starts which helps aswell

I'd be glad to hear valid approaches to get rid of this problem. Thanks in advance LordP