There was nothing wrong with your temps to begin with. If anything they reflect a normal, healthy operating range. If you are having issues with a particular game, the issue would more likely be addressed by a driver update, or a game patch.
Based on the temps you provided, it is HIGHLY unlikely that your software crash has anything to do with overheating. There are a lot of other factors that affect stability. Hyperthreading, overclocking, IRQ conflict, driver conflict, hardware incompatibility, firmware revisions, BIOS revisions, OS corruption, malware, etc. I could go on and on. I would start looking at this from the software perspective. What game are we talking about here, and have you researched any issues concerning stability reported by other users?
Oh, and don't use RivaTuner. It's hopelessly dated. You're better off using CCC, AMD Overdrive, or MSI's Afterburner utility.