To assemble a desktop computer, you need the right components, such as the motherboard, the CPU, RAM, the hard disk and the system unit. You also need tools such as a screwdriver and a small wrench.
First, carefully open the case. Remove the screws at the sides of the case, and then slide the panel down. Take note of cables inside the case. As a precaution, ground yourself.
The first component to install is the motherboard. Install the I/O bezel plate into the opening in the back of the case, and screw the standoffs into the motherboard's mounting holes. Lower the motherboard into the case, ensuring that it aligns with the I/O bezel, and install all the screws.
Next, locate the hard disk bay, and then slide the hard disk into place. Install the necessary screws. Do the same with the optical drive. Afterwards, locate the CPU socket in the motherboard, and carefully insert the CPU. Likewise, locate the RAM socket, and lock the RAM into place.
Place the thermal compound on the CPU, and attach the CPU fan. Next, install the case fan at the appropriate place on the case, and install the screws needed. Connect the power supply, screwing it tightly into place, and then connect the installed components using the appropriate cables. Finally, slide back the case panels, and install the screws to firmly close the case.