Every desktop comes built with a CPU (Central Processing Unit). The CPU is the main chip on your motherboard that carries out the necessary functions of your computer's software. If your HP Pavilion desktop is starting to run slow, you may want to consider upgrading your CPU chip. Each HP Pavilion's CPU capacity varies from computer to computer. Generally, HP Pavilions come with processors as fast as 1 to 2 GHz. HP Pavilion desktop motherboards are only compatible with AMD Athlon and Sempron CPU chipsets.
Shut down your computer, and disconnect the power adaptor from its socket. Remove any miscellaneous peripheral devices from the computer. Rotate the desktop so the back panel is facing toward you. Place the desktop on its left side.
Remove the two Phillips-head thumb screws from the right side of the back panel. Grasp the moulded grip on the side access panel. Slide the side panel away from the desktop and set it aside.
Locate the cooling fan duct inside the desktop casing attached to the back panel. Disconnect the fan's power cable from the motherboard. Remove the retaining Phillips-head screws, or disengage the locking tabs on either side of the fan assembly. Lift the cooling fan out of the desktop casing and set it aside. This reveals the CPU chip.
Determine how the CPU chip is connected to the motherboard. Some HP Pavilion desktops are connected to a CPU socket, while some CPU chips are connected to a slot similar to how RAM is connected to your computer.
Locate the locking mechanism that secures the CPU to the socket. It will either be a lever, or a flathead screw. Lift the lever, or turn the flathead screw in the counter-clockwise direction. If it is connected by a slot, spread the locking latches on each side of the CPU chip and lift the CPU out of the motherboard.
Place the new CPU chip inside its socket. Secure the CPU to its socket by its respective locking mechanism. Replace the CPU cooling fan and its retaining screws if necessary. Re-connect the fan's cable to the motherboard.
Replace the side access panel and its retaining screws. Re-connect the power cable and peripheral devices.
Use an ESD wrist strap. This prevents against damage to your computer's hardware caused by static electricity.