Can you download HWMonitor and post an image screen shot from there? It is easier in my opinion to determine what is the issue or is it picking up a "false sensor", which is actually not reading anything.
I have been running it for about 4 months now, experienced some slowness many times, but thought that it was due to windows 2003 server and the old HDD.
And also, it fails to restart/shutdown, i.e. gets stuck at an empty desktop screen, and I have to manually power it off, could it be a sign of Mobo damage ?