Update
- I launched World of Tanks and the crash with black screen came after some 5 minutes as usual
- I bought a CD and did the Memtest. After 2 passes (1.5 hours) it reports 0 errors so I stopped it. I doubt that doing more passes would bring any useful information because whatever is causing the crashes, it acts very fast and dependably (it is ironical to see that the only thing one can depend upon is that the crash will occur) . The temperature is also not an issue. The necessary and sufficient condition to systematically reproduce the crash and the black screen is to enter a game and wait between 2 and 5 minutes.
