Does it happen both, when using the A/C adapter, and when running on battery?
Download something like speedfan or realtemp to check your internal temps.
Yes it does happen in both cases and like you said I installed Speedfan which shows for my core2duo that 1core is 55C and other one 56C but Realtemp showing 72 and 73. I tried with CUPID's PC WIZARD 2010 which shows thermal zone as 67C and cores as 71C and hard disk is 44C. Are these numbers very high; I suspect they are and if so what can I do to minimize or eliminate this problem.
I've another laptop Toshiba Satellite which has just mobile pentium and it's cpu temp as 63C and hard disk as 42C which originally had xp pro but now has both xp pro and 7 but never had sudden shutdowns.
Thanks a lot for the help, really appreciated.