I just had this problem start yesterday after buying both expansions. I freeze, load slow, flicker. Sometimes it's a hard crash and I have to reboot my system, other times I just alt tab in and out and it's fine, but it's happening any where from every 30 seconds to 5 mins. It's is making GW2 unplayable. I've tried all of the suggested fixes and still nothing. I just wasted $100...