Steam Room Crashes

[Guest7]

I have been at the SteamRoom so long, that my games has crashed a few times. I am trying, (with great hints, thank you all, especially J-B) to get across as best as I can.
After about 5 or more attempts (at one sitting) exiting for a while; then going back for another marathon attempt of 4 or 5 more; taking a break, then going back to do the same thing again, and crash. The whole screen goes black, no movement, no "loading" sign. It stays like that till I re-boot. And I let it sit 10 minutes once, incase the loading was just going slow.

I have to re-boot, at each crash.
What can I do, to keep the game from crashing at the SteamRoom.
Thanks