CLIENT CRASHING DURING LOADIN SCREEN

I am very unhappy with the fact that I've been DEMOTED for games that I didn't even get the chance to play in. The stupid client keeps crashing saying a critical error has occurred during loadin, so then i restart my computer and by the time the client actually lets me back in the game was already remade and I got reported for leaving and DEMOTED BECAUSE I LOST LP MORE THAN 4 TIMES!!! I think it's funny that it works perfectly fine in blind pick and draft pick but the moment I get into a ranked game LEAVER.