TMPIN2 is often the Northbridge in HW Monitor. To verify this, try shutting down and going into the Hardware Monitor function within your BIOS. It may be labeled as Case, Northbridge, or Motherboard there.
And with a temp that high, it's a pretty safe bet there is a definite problem with that motherboard and that this is in fact the cause of your problems. Try running with the side-panel removed and with a fan blowing into the case to see if it helps. If it doesn't significantly lower the temp, then I think you should contact the manufacturer and RMA it. That is, unless you can still return and exchange it at the place of purchase.