A main board support panel retains a main computer board in a computer enclosure. The main board support panel has a plate for supporting the main board. The plate has a bottom edge and an opposite top edge. Two retaining tabs are formed on the bottom edge. Two offset tabs are formed on a bottom plate of the enclosure and gaps are defined between the offset tabs and the bottom plate of the enclosure for receiving the retaining tabs therein. Two retaining lugs are formed on the top edge of the plate. Each retaining lug has an inclined first edge and an opposite second edge with a recess defined therein. Each retaining lug is inserted between first and second bosses formed on the enclosure by moving the main board support panel in a first direction substantially normal to the panel. The inclined edge of the retaining lug slides along the first boss of the enclosure for guiding and moving the main board support panel with respect to the enclosure in a second direction substantially normal to the first direction whereby the recess engages with the second boss to secure the panel in the enclosure.