I cant seem to pick any rhyme or reason for this one other than its a total lockup at seemingly random times when in a GV. I can CTRL-ALT-DEL to bring up windoze task manager to kill the AH process and there seems to be no ill-effects after that. This isnt a CTD or a total hard-lockup which i have to hard-reset. AH just locks up/freezes.
Sorry i cant be more helpful than this as i dont GV much, but i thought it was worth mentioning.