I have had a total catstrophic shut down leading me to the total recovery to out of box state.
Video is not totaly resolved, but functional. Any attempt to game gets failed to render. After attempting to redo drivers from Toshiba. The black screen and blue where all over me. Recovery took forever at least 20 attempts. Attempted to reflash BIOS and it failed=recovery. This unit is limping at best atm.
OS: Vistamized ultimately
Video Card Nvidia 7900
The model: P105-S9339 Toshiba This unit has had many posts similar to this across the net.
Well all of Toshiba drivers and Bios fail Memtest runs without issue.
Could be heat related like you said. Have you checked fans for dust and if fans are actually working? Also do you still have warranty? I know some people get these ridiculously long warranty and if you have one of those you may be covered.
I have a similar model to yours. And I too have scavenged through countless forums in which the same problem had been mentioned.
There has been updates to the BIOS, and I find them making performance even worse off and randomly freezes my laptop. So I just downgraded it back to 4.20/4.10. I find the driver 169.09 from "laptopvideo2go(dot)com" works best. However, I still require the additional help of nTune to underclock my GPU and vRAM to get a stable, non-crashing environment at the expense of HALVING my 3D performance...
It could be heat related, but to an extent that it is intrinsically so to the laptop, i.e. I have cleaned the fans and reapplied cooling gel and been using laptop cooling pads but they just all put off the inevitable when running at full GPU/vRAM speeds. Furthermore, a friend of mine has tried using its laptop's warranty and submit his laptop for "fixing" but to no avail.
I think this is a very deeply embedded problem in almost all laptops, especially the ones that market itself as gaming laptops. The ultimate solution, imo, is simply a desktop. If that is not feasible, I find that macbooks are the best. (in any case, dual boot) They don't have vents beneath whatsoever (only at the bottom of the monitor), but running games at optimal settings are extremely stable (even running on unofficially supported driver software in Windows). It's all down to the matter of technical product design... (not to mention Apple products have great aesthetic design as well!) Until some manufacturers come up with an efficient airflow/cooling structure, I don't think there's much direct and absolute solution to the problem. Problems such as these shall always surface eventually, no matter which vendor you get a gaming laptop with.