A protection circuit to prevent power-on operations for a motherboard includes a first power supply, a spring mechanical switch attached to a chassis of an electronic device, a plurality of second power supplies with different voltages, and a plurality of electronic switches. The spring mechanical switch includes a first terminal coupled to the first power supply, and a second terminal grounded. First pins of the electronic switches are coupled to the first terminal, second pins of the electronic switches respectively are coupled to the second power supplies, third pins of the electronic switches are capable of powering the motherboard. When the cover is detached from the chassis, the mechanical switch rebounds, the first terminal disconnects and the second terminal are disconnected, the electronic switches are turned off, no voltages output from the third pins of the electronic switches.