|Has anyone taken apart the laptop? (possible disturbed thermal bond between CPU and heat sink)|
Has the laptop been dropped? (same or other damage)
Can you tell if the fan is running? (due to bad bearings or badly clogged up)
Sometimes when the vents are badly clogged with dust and possibly pet hair, it is necessary to take it apart to blow out all of the dust. If you are not comfortable doing this, take it to a professional to do it for you. The cooling on many laptops is just sufficient to do the job when it can work properly, blocking even 10% or 20% of the flow can have very significant problems.
You have to be a little bit crazy to keep you from going insane.