A computer system includes a computer casing having a casing wall having an opening to pass through a connection means; a circuit board having the connection means; and a centering means arranged in the casing, wherein the centering means is formed to cooperate with the circuit board such that the circuit board is centered with respect to the casing wall in a direction of the casing wall in a placing movement so that the connection means takes a predetermined position flush with respect to the opening in the casing wall and can plunge into the opening.