I've had the same issue. Logged in today and have the game crash and/or bluescreen shortly after starting. I recently got into beta, but I was able to play w/o issue for probably 4-6 hours over the last 2 nights.
To my knowledge, the only thing that changed on end is Steam had an update (I have the Steam version).
I to have noticed, I have been crashing at least almost every 5 minutes, And I was able to play fine with out any crashes since i joined beta on the 13th. I hope they get to the bottom of this cause it makes questing and other thing close to impossible.
Not comcast, i have Time Warner here in North County San Diego. I tried a brand new GTX 260 series OC and same issue, so i put it back im my computer i use for school. not sure what it is, but its not on my end