How to replace mother board - Computers & Internet

Assuming you have the correct sized replacement (motherboards are all different sizes and have external ports at various locations), you'll need to unplu all external cables/device, put the machine at a static safe location like a kitchen table - don't work on a rug, open the case, then disconnect the power supply cables to the old motherboard, drive cables, and remove any installed cars and memory. You may have to physically remove drives and the power supply itself for access. Once you have everything out of the way there are usually 6-8 Philips head screws holding the motherboard in place. Remove those and lift out the MB. Installation is the reverse order of removal.

I've posted a link to a good video that gives a general overview of the process.