I started experiencing the BSD last year around this same time, I about went insane (it would shut down after many hours playing TS1, losing all my work). I spent a couple of hundred dollars having a tech "repair" it after I had spent countless hours researching the problem and trying to fix it myself. Turns out the "tech" only reinstalled windows and after about 5 wks I started getting the same exact problem (and no, they wouldn't waive the diagnostic fee to look at it again
). Anyway, I ended up just buying a new computer. Several months later I took the old computer to a different tech place, described the problem to them, they found it odd and took off the case.....where the discovered a wad of dust/dirt/hair trapped that was causing the computer to overheat, resulting in the BSD. Aaaargh!! It's been running fine ever since. So, I would check out the inside of your tower and see how clean/dirty it is and also the fan to make sure it is working properly.