How do I update the drivers for my AMD Athlon(tm) II X4 640 Processor?

I dont know if I can be of much help, you seem to be on top of things. A couple things I would try is maybe typing the CPU name on Google followed with the word drivers, it may provide more options than just getting the drivers from AMD. If you have recently added new parts like video card or sound card, try switching back to the original part to see if it solves problem, or do a selective start up, starting components one at a time until you find what is causing the problem. Good luck.