This happens from time to time. At least once a day. I will log into AH then select the arena I wish to go into, then halfway through the loading the arena, my comp shuts down. This happened to me this morning three times before I successfully go completely into the arena. I have found that once I am completely into the arena that I am safe. It is not a overheating issue, as my comp was shutdown the overnight, then started up this morning.
Thanks in advance,
BowHTR