You have a power supply short somewhere. The clicking noise is probably the polyfuse blowing and resetting. Check you don't have any small metal objects lurking around on the pcb (screws, metal filings, crowbars, etc). Remove the power supply jumpers labelled +3V (one jumper) and +5v (two jumpers) and try again. If you don't get the noise, the short is in the main circuitry. If you DO get the noise, the power supply probably has a fault.

If it's not a loose bit of conductive crap, you may have a fairly serious problem

pca