Well, in the other thread you were saying that your fsb was at 133, and your cpu was running at 1.7 Ghz or so. Then you bumped it to 166, which now has it running at 2.17 Ghz. Your memory is PC2700, so it should be fine at 166. I would look at cooling first, then the memory.
Before you bumped it to 2.17 Ghz, you didn't have any problems, but now you do. I would start with the cooling, as others have said. Did you install the heatsink properly? Did you use thermal grease first? What is your case temp or motherboard temp compared to your processor temp? Do you have adequate ventilation? These questions are easy to answer and a good place to start. You can always drop your fsb back to 133 and see if your temps drop and your pc stops crashing.
And in my mind, 57C idle is way too hot. Once you start playing videogames it will make your temps go even higher. And as was said, Asus Probe and other software temp utilities are not all that accurate. I would consider the reading a ballpark figure at best.