When I was playing Foldit today, my laptop (which was recently upgraded to Windows 7 Home Premium from the corresponding 32-bit edition of Windows Vista) suddenly shut down without a warning... again.

Sadly, this is not an isolated incident-- this had already happened multiple times when my computer was still running Vista. Overheating was considered as a possible cause, but checking the HD temperature readings ruled out this possibility (plus, if that were the cause surely some other CPU-intensive program would also do the job). Given that this has happened only when Foldit is being run (i.e. it never happens to my other programs) *and* under Windows Vista/7 (running Foldit under my previous Windows XP SP3 laptop never caused a spontaneous shutdown), I'm wondering if there could be a compatibility issue. For your information, automatic restart upon system failure was turned off.