Answer: If you want to upgrade your processor you most likely will need to upgrade your motherboard as well. Motherboards are designed to fit with only a certain type of processor. So if you have a Pentium 3 and want to upgrade to a Pentium 4 or switch to an AMD then you will have to have a motherboard that supports that particular processor. It may be possible to upgrade to a faster version of the same processor depending on the motherboard. For example if you have a Pentium 4 that runs at 2.8 GHz and want to upgrade to a Pentium 4 that runs at 3.2 GHz your motherboard may support both processors. Keep in mind that if you replace the motherboard that Windows most likely will not recognize it and not run. You can do a repair installation of Windows before booting the computer to have Windows recognize the new motherboard.