1.)Open the right side panel (right from the back of the case) which is usually held together by two screws. Open it carefully. You will now see the motherboard mounted on the wall of the other panel. You may want to use a grounding band as any static electricity may damage the internals.
2.)Now carefully disconnect all the wiring and keep them aside (Label them so that it'll be easier to install them later.
The flat wire (usually colored) is the SATA. This connects the HDD and the Optical Drives to the motherboard.
3.)Now, there will be some screws holding together the motherboard with the panel and after unscrewing them, the motherboard should be separated.
4.)Now remove the RAM which will be located on the side of the processor. Do this carefully as there are clips at either side of the socket.
5.)After doing this, remove the graphics card (If any) which has been installed which should be above or below the processor (Depending on how you have kept your motherboard).
6.)Now, remove the CPU cooler by locating and twisting the four 'plastic screws'. These will hang from the cooler.
7.)Now, without applying any pressure to the middle, lift the metal 'stick' which should be tucked under a notch and slowly move it upwards. Get the cap out of the way and remove the processor gently and place it in a place which won't damage the underside. Also, don't touch any of the exposed pins from the motherboard or from the processor.
8.)Now, get the new motherboard and fix the processor gently but tightly. Without touching or pressing the processor, bring the metal 'stick' down and tuck it under the notch. Also, be careful while placing the processor as there are notches in the motherboard too and if it is placed wrongly then you may damage the processor.
9.)Now, install the cooler by firmly pressing down on the plastic screws and twisting them, and then connecting the wire to a port labelled "CPU Fan".
10.)Now add the RAM to the slots and press it firmly and close the clips.
11.)Add the graphics card (If any).
12.)Proceed with the wiring. Don't panic as the wiring only looks difficult. The slots for the items on the cabinet are usually below the processor (Again, depends on how you hold it). The wires from the power supply may look dreadful, but apply some basic logic and you will be good to go as you have to match the slots with the pins and they usually have their own unique pattern (For example, one might have a blank spot and will be shaped differently. Also, counting the pins and sockets will help).
13.)Now, fix the motherboard to the back panel (You can also assemble the components while you have fixed it to the back panel).
14.)Now fix the other side's panel and connect the power supply to the plug in your house/office/hotel/other.
15.)Switch on your PC and install the new motherboard's drivers.
Important Notes: You MUST unplug the power supply and ensure that no current is passing through the PC while you are assembling.Also, make sure that no cables (Connecting the PC to the monitor or speakers et cetera) are connected. I will strongly recommend that you watch videos on the assembly and dis-assembly of similar computers in addition to reading such tutorials before doing this in real life.
Hope I have helped you all,
Notice- I cannot be held responsible for any loss caused during the replacement. This tutorial is not an official training. There may be other people having tutorials on the same topic, but this is written solely by me and I have not copied this content from any other user(s). I thank you for taking the time to read this tutorial and hope from the bottom of my heart that I have helped each and every one of you readers. Thanks again.