Can you tell us a little more about .I`m not familiar with AMD CPUs.Is this an Athalon 64 x2 dual core 2.0 ghz 512 +512 mb l2 cache socket AM2?I looked at there site,but there is alot of info to search through.
Is the heat sink firmly atached? It happens to me once as follws. I had a amd 64 3200 with a hyper 6+ heatsink. Since you have to remove the original heatsink retention mechanism, it became useless. Then I change of case and the my hyper 6+ did not fit. I tried to use the original heatsink and retention mechanism,, but since it did not make a good contact my cpu went to over 70´s. Back to the old case and hyper 6+ and voila!!. I even change to an amd 64 x2 4600 and my temps are below 35°c under load!!
Sounds about right. Normal idle temps on those CPUs are about 33-36C max if I recall correctly.
Best bet Christina is to simply power down, remove the HSF, remove any thermal paste, and redo it from scratch: new thermal paste, spread it properly, remount the HSF, check that everthing is tight and seated flat, etc. Then power up, go directly into BIOS and into PC Health (or something like that). Watch the CPU temps, let the computer run for 20 minutes and see what happens.