I've decided to put my PC out of its box and install in on the wall. Advantages: no more dust stucked in the PC box and dust fly away immediately from the wall mount thanks to the various fans that are installed. The components here will allow you to install the ATX power supply, the HDDs, a graphical card (an AMD Radeon R9 390X) a wooden board. The fan on the right side of the HDDs is a 120 x 120 mm fan. To deport the graphic card you'll need a PCI-e X16 Riser Cable I covered my wooden board with a "carbon like" sticker.
The "kill switch" for the power on and tth reset are available here: https://www.thingiverse.com/thing:4313332