Try testing the system out of the chassis, with minimal configuration such as Motherboard, processor, power supply, 1 memory stick and video card, to find out which component is system to reboots.
The processor will send a signal to the motherboard to shut down to prevent mayor damage if the temperature is close to the 100 degrees Celsius. You processor is handling temperature around the 35 and 40 degrees Celsius, so it is perfectly find.
You may want to test the system with different RAM.
This kind of issue could be cause by memory, operating system, motherboard or the processor itself.
So what we can do is to narrow down the problem in order to find out which component or software is causing the system to reboots.
The temperature is perfectly ok, I thought the information given was on degrees Celcius instead of Fahrenheit.
Our recommendations will be:
• test one memory stick at the time.
• test a different memory stick.
• You may want to do a clean instalation of the operating system.
• Test another processor on the motherboard
• Test the processor on another motherboard.