I need help ASAP am dying

RIOT people please help me my game non stop crashing. I use to play regularly and there was no issue, and then i took a break for a few months and started playing again. It started with a just one crash/freeze. My game freezes and so does my computer. I can open task manager but i cant see it? like the league game is stuck on my desktop ig? So while task manager is open I cannot tab in to it. I end having to restart my cp everytime and it does let me reconnect to games. The first time it happened I didnt think much of it ,but the more it happens the more frequent it becomes. First it was the only crash for a few days. And then maybe every 2 games it would freeze. Now its multiple times a game. I already got 1 afk ban and I think i just got another. I checked my league files and none of them are corrupt. I do not know what to do. I am windows 8.1. All help is appreciated. (;

EDIT: recently my spottily has been acting up as well so i used the good old trouble shoot and it said it detected in compatible program and then it fixed it. Just did same thing for league, same issue. Incompatible program. Fixed it hopefully it wont crash now?