Download a PC-compatible MIDI controller interface (see Reference 1). There are many of these programs available online for free as well as for a small fee.
Install the MIDI controller interface by double-clicking on the .exe file and following the prompts given by the Installation Wizard.
Double-click on the MIDI controller interface to open the program.
Select the "guitar" function under the "Instruments" or "Sounds" menu.
Press and hold down on the keys corresponding to the notes G, C and E on your PC's keyboard. Most programs have different keys assigned to different notes, but offer a map of the notes and corresponding keys under the "Help" menu.