Select from the dropdown lists to complete the text.
In order for a PC to function, it must have a ( CPU, RAM, PSU ) connected to the motherboard via a heat-sink, have sticks of ( RAM, POWER, PROCESSOR ) installed on the motherboard, be connected to a working ( PSU, DISK DRIVE, CPU ) which gives the computer its electricity. It must also have a ( hard-drive, motherboard, CPU ) to install the operating system on and to allow it to store and retrieve data.