Restarts usually are indicative of hardware problems, but you make it unnecessary hard fot the PC with those large JPEG's. First reduce the size of those JPEG's in PS to something much closer to your final output. Maybe that helps, but there is probably more wrong under the hood.
Thank you! I've already resize the stills with a smaller size and it doesn't crash. It was the size of the .jpeg.
I think my computer has some kind of hardware problem like you said, because when i shut down the computer it closes everything but the fans continue working as well the led power. I have to cut the power supply to completly shut down the computer.
Sounds to me like you've got a power supply problem. With a powerful computer doing powerful work (like video or CAD), you have got to have a solid power supply. I generally will calculate the power consumption needs of my hardware and then give it at least a 20% headroom before deciding on a power supply, and I never buy the generic cheap power supplies... There's a handy power supply calculator here: http://educations.newegg.com/tool/psucalc/index.html?Tpk=power%20supply%20calculator