Same problem here; Black screen, last second of sound loops a few times and i need to hard reset manually..
Never had this before with GW2 or any other game untill i started playing after the patch again today.
So 3 pages of people who have a problem which is obviously related to patches for GW2 since everyone has a diffrent system running it, and still no tech support reply.
Patch the kitten game so I/we can play hours and hours without having to reboot ever30 to 60 min..