I think We are on the right way about this problem.Yesterday I took the exact same laptop, put it's cpu in mine and there was no problem. I used same programs, installed updates, drivers, .net framework... These things triggered bsod before, with old cpu.I also put my cpu and hdd in second laptop,tried to trigger bsod in a way it was happening before; I started with installing chipset and heci drivers, after that drivers for gpu (which is ati radeon 5150) and Windows bsod-ed after installing gpu drivers (as it was happening before). I finished with this, didn't test it more.
I'll send it to Local Toshiba Service.