For starters, you need to make sure it's the switch's fault.
Open up the case and with a screwdriver connect the pins on the motherboard that go to the switch. Make sure you connect only those pins! If it boots up, then, yes, it's the switch. You will need to get the case's manufacturer to help you with that. Or you can improvise, but will not look too good.
Thank you, will try that, I have two systems using this case, same motherboard and so on, so can swap out parts if necessary.
As to the case, there are no identifying marks, or any other information on it, so guess it's a shot in the dark if this doesn't work.
Will let you know.
Again, many thanks.