Spontanious reboots

It's certainly possible. Do you play a lot of graphics intensive games?

You can usually check your CPU's temps in the BIOS.

Normal idle temp should be about 45C. If it's over 50, you may need better cooling. Does your motherboard come with some sort of monitoring software? If not, you can download motherboard monitor 5.2 to keep an eye on your cpu/system temps, fan speeds, and voltages.

How strong is your power supply? Make sure its an AMD certified model. You can go to www.amd.com to check.

You may also want to get MemTest86 to check your RAM.

Motherboard has this feature but once it starts I can't keep it running long enough to check.
I replaced my 1800+ with the 2100+ so everything has been running okay. I suspect I need better cooling and going to try that first. It only happens if I leave the machine on for several hours.