i had the same problem w/ my lappy...
i was working on it but i was forced to reformat due to an unrelated problem. long story short... it doesnt restart on its own any more.
if your going to go this route make SURE you got a reliable
firewall and bug killer BEFORE you get back online after the reformat. (i say this b/c not ten seconds after i reset-up my connection to the net i got hit with the msblastworm....
well... goodluck