Have you opened the case to the pc and cleaned it out with air since you have had it? Make sure you ground yourself to the case before touching anything inside and that the pc is off and unplugged from the wall and just ground yourself by holding on to the case or by using a grounding strap. Use compressed air to blow out all the dust and make sure the vent holes where the fans pull air in from are clean too. You should be able to check cpu temp in the bios which will give you idle temp with no load on the processor and there is a couple of software monitors that will give you the temp of the processor at all times like motherboard monitor which is my favorite even though I haven't used it in a while. You can download it here at
http://mbm.livewiredev.com/download.html