3. Find a large space for workspace. Changing a motherboard requires a lot of unscrewing the parts and so, you might want to consider doing it in a large open area. Although you might find it reasonable to open your CPU on a small table, it’s ok, as long as you can remember where you placed the screws (and as long as you won’t find it annoying to go to and fro the places where you’ve placed the parts).
4. Make the puzzle fit. Newer versions of motherboards use another kind of power supply and have a 24 pin slot for the connector. If your computer is relatively old, the cord for the power supply might only have 20 pins on it. Although it is possible to do this, it is somewhat risky since you will deliver insufficient electric supply to your motherboard.
Photo taken from http://www.icpamerica.com