Just remembered that you're using a Brisbane, the temp sensor does not work properly, there is no sure way of knowing the exaxt temp of the proc. Best way remaining is to feel the base of the heatsink, if it feels warm but not hot then its still ok. For other processors where the temp sensor works properly, make sure temp of either core does not go above 65 (don't add up the temp). If it does reach that high for a short while (like a few hours), no problem, but running for weeks at that temp is risky. 70C is about the limit before the processor lifespan get shortened noticably, though it will not affect the proc if its just for a while, but it recommended that you stop immediately. Processors in general don't die that easily from overheating anymore because there are safety trip-offs, its usually voltage that kills processors nowadays. Always be careful when playing with voltage, take advantage of others' experience. Voltage tweaking is particularly tempting to use despite the risk because its the one of the most sure ways to allow for higher overclocking.

For a start keep the multiplier high while increasing the HTT, don't touch the voltage yet. Spend time tweaking around other settings, none of them are particularly dangerous. Anything wrong, just reset the BIOS. AM2 is particularly sensitive to memory settings, keep that in mind.