You have provided invaluable information. I certainly have more to go on than I did before.
As for as the temp sensor... I have no knowledge of the problem. I did remember reading about the issue on the MSI forums for misreadings with the utiliy that is provided. But that's all I can tell you. Everything works on the K7N2 - WinXP system (I'm on my old pooter at the moment) except, of all things, OP. Ah well... it's hard to garner any sympathy for a single game. But, it's the only game I really care about.
For what it is worth... the system hasn't cost me dime one thus far. If, for a modest investment, I can smooth out this problem then I will still be fortunate. Except for the year it has taken off of my life... kidding, really.
Again, thank you greatly for the information you provided. I knew I was at the point where it would take components to troubleshoot and what you have told me gets me there in part.
Peace.