Launcher crashes after starting the game/+ minecraft uses up way too much CPU suddenly

the launcher crashes after loading in the game, saying game crashed.
also, for the last few weeks, minecraft suddenly used up 100% of the cpu, which didn't happen before(the time is after the last windows update.)
and now it doesn't open. also, whenever I try to attach the launcher log, it says JIRA could not attatch the file as there was a missing token, please try attaching the file again.