I unplugged the power board my G5 is plugged into from the wall socket and moved the whole thing three feet onto a new desk. I then plugged the power board into a new socket. From then on the power indicator light has remained lit on the front panel of the tower without me having pressed start. There is no other sign of life, no fan, no screen power, no other audio. The 'ON' button has no response to being pressed or pressed and held down. All cables are firmly in place, and when I turn the power off and on again at the socket it returns to the same state.

Can anyone shed any light on this?
Can anyone shed any light on this?