Client randomly closing and login issues

After a game there's a 50/50 chance that the client will close entirely (without prompting or warning) instead of taking me to the post-game lobby, which isn't normally an issue except for when someone needs to be reported but still I like to talk to my teammates and the other team when a game's over, so this is kind of a pain. It will also happen when I'm spectating a game; and when the spec'ds game is over or I stop spectating of my own volition the main client is again, also closed.

The login issue I've been having for the past two patches. Frequently when logging in, even though it makes the 'click' noise I won't be actually logged in and will get a "disconnected from pvp.net" error. I've tried multiple fixes for this one, including flushing DNS and running the client as administrator, these don't do anything. I'm rarely ever able to login on first try now, and have to restart the client anywhere from 3 to 10 times to log in successfully. This isn't an issue with my internet either because I'm able to log into other servers like EUW and the PBE first time every time.