Computer casing with fastening device

A computer casing comprising:

• a computer cage;
• a top panel attached to a top of the cage, the top panel having a sliding slot defined therein, a plurality of through holes defined in communication with the sliding slot, and a plurality of recesses defined in one side of the top panel and in communication with corresponding through holes;
• a fastening device slidably accommodated in the sliding slot of the top panel, a plurality of through openings being defined through the fastening device in alignment with the through holes of the top panel;
• a resilient member positioned on one end of the fastening device to provide recovery force for the fastening device;
• and
• a side panel attached to one side of the cage, the side panel comprising a plurality of hooks, wherein when the hooks are extended through the recesses and through holes of the top panel, the hooks drive the fastening device to slide along the sliding slot and compress the resilient member, and when the hooks have entered the through openings, the resilient member decompresses and pushes the fastening device to snappingly engage the side panel with the top panel.