On the builds where I used the whole PC, I made a shelf for it to sit on, then 4 blocks, 1 front, one back, and on either side of the PC case. (low profile blocks, like 1 X 2 inches)
Then a wood brace across the top. This keeps the PC from shifting even while transporting the cabinet with it laying down on its back.
But this may not be a good method for one who is lazy at heart.
