COMPUTER DISASSEMBLING STEPS.
-Turn off the system unit and unplug the AVR (Automatic Voltage Regulator) from the wall socket.
-Unplug all the cables connecting to the back of the system unit. After clearing all the connected cables, put the system unit on an empty working table.
-Remove the screws of the side cover opposite to the side where the ports are and the return the screw back to the screw holes to avoid losing them.
-Once the side cover is removed turn your system side down where the opened side of the system unit should be facing upward.
-Disconnect all wires from the motherboard leading to the power supply, switches hard drives, CD/DVD/Blue-rays/Floppy drives from USB and fan cables and remove all PCI (Peripheral Components Interconnect), PCI-E (Peripheral Components Interconnect Express) and any removable cards or cables.
-Locate the mounting screws for the hard drives and other removable devices and remove them from the computer.
-Locate and remove the screw on the power supply on the rear of the computer and the PCI slot covers and remove the power supply from inside the computer.
-Locate the screw from the motherboard and remove them carefully, remove the motherboard stand offs as well, then remove the motherboard. Remove all hard drives from the computer, power supply and lastly motherboard.
This is the reverse process of disassembling.