>>>There are 2 cards in the motherboard
A CPU is not a "card", these cards are probably the memory sticks.
Have you definately got a fan on top of the CPU and is it running. It will look something like this (they do vary in size and shape).
http://media.bestofmicro.com/system-Buider-2009-Gaming,C-5-224645-13.jpg
When a fan is placed on top of the CPU a type of glue is put on the bottom of the fan to get a good seal between the fan base and the CPU.
If the fan has become dislodged from its fixings, and the "glue" separated between the fan and CPU it may not be getting a good "seal" with the CPU.
My main suggestion would be to buy a new fan, you can get one fairly cheaply, and fix this to the CPU. It will probably come with the glue already on it.
I bought a new Akasa fan the other day for an Intel CPU and it only cost me about £5 and came with the "glue" already on the base of the fan.