I wanted to make an htpc that blended in with a home theatre. A friend had a gutted receiver kicking around, so I used that as the case, and parts from a pc that I wasn't using.
Step 1: Tools
tools used were drill, bits, dremel, screwdriver, ruler, and soldering gun.
pc components consisted of a gigabyte motherboard, 500 Gb seagate harddrive, thermaltake 430 watt power supply, HIS radeon 5450 silent video card, and a scyth low flow fan.
I used linux mint as the OS.
First I had to align the parts inside, and figure out how everything would fit. Once that was done I lined up the motherboard and marked where to drill the holes for mounting. I made sure to leave space under the board to allow for airflow. I also drilled a few holes on the right side to allow for more air to get to the video card.
Step 3: Wiring
There were momentary switches on the circuit board as well as lights, so I soldered the power switch and 2 leds to use as power and hard drive lights. There was also a usb plug on the front, which I had to resolder to the correct configuration, it was wired for upgrades and diagnostics only.
Step 4: Back Plate
Next I cut a piece of sheet metal I had for the back plate to mount the power supply, motherboard plate and a slot for the video card. I used existing holes in the case for the mounting.
Step 5: Fan
I mounted the fan on the inside of the case, above the video card and processor, to exhaust the heat from them.
Step 6: Finished Product
The finished product, an htpc that looks like a receiver. In the first picture you can see the desktop screen. The second, it has web connection. In the third, the htpc is on the left, with wireless keyboard, connected to the receiver on the right.