Game is unplayable

Okay so like idk what the problem is but my game is soooo laggy and glitchy ever since the marketplace update and I've tried literally every solution I could find. I've uninstalled the game, gone through my cc, deleted cc blah blah blah and no matter what I do when I go into live mode to play my game it either is completely black besides the menu tools stuff or whatever or EXTREMLY glitchy and idk what to do anymore.