Several Issues with Playing League on Recent Patches

This seems to be the most appropriate sub-heading to request help. Over the last few weeks, I've faced some severe FPS issues and more recently, my PC crashed in champion select on two occurrences. Once, I was unable to load into a game even though my champ select showed 100%. It wasn't stuck, I could still move my cursor and hover over runes and so on, but I didn't load into game, until eventually my team remade and I was shown the post-match screen. I've never really had issues with playing League on this PC (one and a half years old) until patch 9.14. Any tips on what I could do would be appreciated.