HP Compaq Presario,Presario CQ42-121 Maintenance And Service Manual page 99

NOTE:
assembly and system board components, it may be necessary to move the fan/heat sink
assembly from side to side to detach the assembly.
4. Remove the fan/heat sink assembly (3).
The thermal material must be thoroughly cleaned from the surface of the fan/heat sink assembly (1),
(3) and the processor (2) and video components (4) each time the fan/heat sink assembly is
removed. Thermal pads and thermal paste must be installed on all surfaces before the fan/heat sink
assembly is reinstalled.
NOTE: Thermal pads and thermal paste are included with all fan/heat sink assembly, system board,
and processor spare part kits.
The following illustration shows the locations for thermal material on systems with discrete graphics
subsystems.
ENWW
Due to the adhesive quality of the thermal material located between the fan/heat sink
Component replacement procedures 89