Plutonium

My game keeps alt tabing after 2 hours of play time when I try to alt back it keeps kicking me the game didn't crash I can still hear the sounds and my self dying?

I need some help with bo2 every time I try to play zombies solo the game loades but it gets stuck on awaiting challenge how can I fix this then the game kicks me out of the loading sreen and it will say you have been disconnected from bo2 server's