I have recently acquired a second-hand Activboard on behalf of a charity Second Generation Board I believe). Unfortunately it is not working, possibly due to damage in transit. It is out of warranty.
The problem I believe is known as "spiking".

I contacted Promethean support who have offered suggested solutions very promptly and efficiently. I am most grateful for their excellent response.

None of these suggestions have made any difference and the final email concluded:
"We have now checked every option possible without finding a solution for the issue described which would indicate that the hardware has become faulty. The only way to test this would be with another set of electronics.
As the warranty for this board has ended in 2012 and we are no longer able to provide replacement electronic. Therefore we would like to suggest that you contact our reseller to purchase replacement electronic."

The charity is unlikely to be able to afford to purchase new electronics. Before going down that route, I thought I would check the forum to see if there is any way to check out the rest of the board, without the electronics - i.e. the grid of wires which connect to the electronic circuitry. I have some electronic experience and would be able to carry out continuity checks etc.

Any experts out there to advise me?

Incidentally I have tried the following:
Different power supplies;
Different lengths of usb lead;
Different laptops with Windows xp, 7 & 8(64 bit)
Different drivers: ActivDriver_x86_v5.8.46, ActivDriver x86 v5.7.22.1, ActivDriver_x86+v5.9.27
Upgraded firmware to 3.75