We have the 3 7-segment displays separated, I've put them together using super glue.
I got a project box which I've dyed in order to match my case, mouse and keyboard.
I've made a hole for the printer cable and now it's time to make a hole for the 7-segment displays.
The final step, soldering the 7-segment displays. To know which are the pins for each segment take a look up at "Here's how you can determine which type your salvaged 7-segment is". But this time take a look at which segment lights up.
The final product! Of course the PCB goes into the box, this is just to show you all the parts. Sorry about the pic, my camera's flash is very powerful but you can see the "35", my CPU temperature.
Here you can take a look at the space that is required for this circuit, you can put it in a 5 1/4 bay if you want.