A fastener buckles a hard disk driver (HDD) in a first fasten portion of a case. The fastener comprises a second fasten portion and a third fasten portion. The second fasten portion buckles a first hole on the HDD. A first side of the third fasten portion connects with the second fasten portion. At least one part of the third fasten portion buckles the first fasten portion so that the HDD is fastened to the case.