You need to change the motherboard when you upgrade from a P4 to a Core2Duo CPU.
Upgrading your processor is one way to instantly add performance to your computer. A Pentium4 with Hyper Threading can be upgraded to a Core 2 Duo, but only if the motherboard is also changed out. This is because the Core2Duo and P4 chips use different socket types. Motherboards are made to accommodate only one type of CPU socket.
Instructions
1. Unplug the computer to reduce the risk of electrical shock and remove the side panel to access the inside of the computer.
2. Disconnect the components from the motherboard including the power supply and any drives (hard drives and disc drives).
3. Remove any PCI-X or PCI cards from the motherboard. These cards are screwed onto the case with a single screw in the back of the case. Remove the screw and yank out the card to remove it.
4. Unscrew the motherboard and remove it from the case. The screws should be along the edges of the motherboard with one in the middle.
5. Remove the RAM from the motherboard by unclipping the top and bottom of the RAM.
6. Place the RAM onto the new motherboard. Place it into the slot then push the top and bottom down at the same time to clip it in.
7. Insert the Core2Duo CPU into the socket and clip it in using the latch on one side of the socket.
8. Place the heatsink/fan unit on top of the CPU, then clip it into the motherboard in the four corners of the heatsink/fan unit.
9. Place the motherboard in the case and screw it in.
10. Reconnect the power supply and any drives.
11. Reinsert the PCI-X or PCI cards, making sure to screw them into the case.
12. Close the side panel.
Tags: from motherboard, heatsink unit, PCI-X cards, power supply, power supply drives, side panel, supply drives