HP Compaq Presario,Presario C300 Maintenance And Service Manual page 158

Removal and Replacement Procedures
✎
The thermal paste should be thoroughly cleaned from the
surfaces of the processor 1 and system board 2 and the
fan/heat sink assembly 3 and 4 each time the fan/heat sink
assembly is removed. Thermal paste should be reapplied to
both surfaces before the fan/heat sink assembly is reinstalled.
Thermal paste is included with all fan/heat sink assembly and
processor spare part kits.
Replacing the Thermal Paste
Reverse the above procedure to install the fan/heat sink assembly.
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