hey guys.. im posting this on behalf of my friend.. her desire S apparently randomly auto restarts.. it happens once or twice a day on average..
it doesnt seem to be a heating problem, as the phone does not get hot when it restarts.. it heats up a bit during heavy gaming etc but nothing abnormal, it doesnt restart during this period..
unfortunately i cant give u any more detail as i dont use it. phone is not rooted
i noticed some similar threads on the Desire forum but i thought i'd post this here as this phone is newer n shouldve fixed any problems with the old desire 
it doesnt seem to be a heating problem, as the phone does not get hot when it restarts.. it heats up a bit during heavy gaming etc but nothing abnormal, it doesnt restart during this period..
unfortunately i cant give u any more detail as i dont use it. phone is not rooted
i noticed some similar threads on the Desire forum but i thought i'd post this here as this phone is newer n shouldve fixed any problems with the old desire 