I'm going to assume it was yourself, or someone besides a tech, who installed this motherboard.
A tech would have the machine working before giving it back.
A) What was the original problem? Why motherboard replacement?
B) Do you know for a fact that the replacement motherboard is a good working unit?
Bought from a reputable dealer, or history of motherboard is known?
C) Did you follow Anti-Static Precautions, and used a ESD wrist strap, and connected it's alligator clip to a good ground source?
D) How acquainted are you with the design of a laptop's cooling system?
Aware of the basic design?
1) Air is drawn in for the cooling system usually from the Bottom of the laptop.
(Air Intake Duct. It is expelled through the Exhaust Port)
2) The air is drawn straight up into the cooling Fan.
Air then is pushed through the fins of the Heatsink
There is a Cooling Tube usually made of Aluminum or Copper. One end is attached to the finned Heatsink.
The other end is usually attached to a small metal plate.
This metal plate sits on top of the Processor.
Heat from the Processor is absorbed by the small plate. The heat is then transferred to the Cooling Tube. (Cooling Tube absorbs heat from the small plate)
The Cooling Tube then transfers the heat to the Heatsink.
The Heatsink absorbs the heat, then radiates it away with the tall, thin fins.
Air going through the fins, and around the fins, helps to carry the heat away.
Also on the same end as the Processor, is usually another small metal plate. This plate sits on top of the GPU.
Graphics Processing Unit, or simply stated as the graphics chipset.
(Essentially the 'Graphics Engine')
The Processor, and the GPU, are the TWO hardware components that PRODUCE the most HEAT.
Example of basic laptop cooling design I referred to above,http://www.insidemylaptop.com/disassemble-hp-pavilion-dv6-laptop/
Scroll down to Step 29.
Here you see the black Fan Assembly.
To the immediate left of it is the finned Heatsink. Black in color, fins are not visible.
Coming down on the left from the Heatsink is a copper Cooling Tube.
Most of it's length is attached to an aluminum plate.
(Three machine screws hold the plate to the motherboard)
The aluminum plate you see is covering the top of the Processor, and also the GPU sitting next to it.
In looking at the Heatsink/Fan/Cooling Tube combination, for the HP
Pavilion dv8000 series of Notebook PC's, I do not see a metal plate for
I only see that the Processor is covered by a metal plate.
Heatsink with copper Cooling Tube attached, and small metal plate at the end for the Processor,
This means there is no cooling for the GPU, except for air that may make it's way around, in the inside of the laptop.
A GPU is mounted to the motherboard with a BGA Surface Mount.
Ball Grid Array.
To explain a BGA surface mount;
Your motherboard has an AMD processor socket (Mobile) that an AMD processor fits in.
The socket has the socket holes, and the Processor has the contact pins, which go into the socket holes.
With a BGA surface mount there are no contact pins, or socket holes.
There are Copper Pads, and Solder Balls,http://en.wikipedia.org/wiki/Ball_grid_array
The bottom of the GPU chipset has Solder Balls.
The surface of the motherboard has matching Copper Pads.
The GPU is set into place with the Solder Balls lining up, to the matching Copper Pads on the motherboard.
Heat is then applied at a certain specific temperature, and length of time.
The Solder Balls melt, which solders the GPU to the motherboard.
(Solders the GPU to the Copper Pads on the motherboard)
IF, a GPU constantly overheats, the solder connections start to melt. This creates cold solder joints, and a black display on the laptop's internal monitor.
A) The motherboard that has been installed may have the same problem as the original one, if the problem was poor contact for the GPU.
B) If you did not follow Anti-Static Precautions, there's a good chance the motherboard is now an expensive paperweight, or doorstop.
For additional questions please post in a Comment, or to reply