TOPIC: Help

I can't play because when i join servers my computer freezes up and i have to wait for it to kick me for being slow. It only happens on servers and not on my single player game. I also for whatever reason can't use the arrow keys while typing a forum post or the page freezes up and i have to open a new tab and try again. Please help.

Edit: Restarted computer and i can join servers and not have them freeze up my computer. Still can't use arrow keys on forum posts.