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#11
Was your system at idle when you took the Core Temp readings?
Even if it wasn't, those temps are high. AMD's max temp for your CPU is 62°C.
Have seen overclocked AMD CPUs running at mid 40's.
AMD Phenom™ II X4 955
When putting a load on your system it will generate more heat, when the heat becomes too high the CPU will start to throttle down, if that doesn't help it will shut down.
This may not be your only issue but, needs to be resolved before any more troubleshooting.
AMD CPUs usually run very cool.
Are you using the stock CPU cooler?
Have you checked or changes the thermal paste between the CPU and cooler?
With your system shut down, see if you can rotate the CPU cooler, don't move it more than a fraction of an inch.
If it moves it is loose, it will need to be taken off, cleaned and new thermal paste applied, then the cooler re-installed.