A fastener for mounting a heat dissipation module on a central processing unit, includes a shank having opposite upper and lower ends and a head at the upper end of the shank. The shank includes a first portion located between the upper and lower ends, and adapted to engage, by snap engagement, with a fastener retaining portion of the heat dissipation module. The shank also includes a second portion located at the lower end and adapted to engage with a matching mounting element of a base, thereby fastening the central processing unit between the base and the heat dissipation module.