I can't get away from the fact this occurred after you added memory. What is the chance of some other problem happening to occur at the same time? About zero? Whether or not it is directly related to the memory, who knows. Perhaps you touched something and discharged static? Moved a wire?
I would be going in checking the Power On, Power OK signals but since nobody ever seems to have a digital multimeter, I mention it for the record only!
I can't see it being the PSU itself or voltage fluctuations. I suppose it depends on the setup but power problems should turn off the supply and require cycling of the main breaker to reset.
What is the motherboard model? Can you locate the source of the click down to a device with a part number or a photo of it? A stethoscope would be good to trace the sound. Personally I would use my finger (after discharging static on the chassis) or a short plastic rod. One occasion where a grounding strap would be highly dangerous. At this point one has to assume the MB is probably done for, so there is little to lose.
I would be going in checking the Power On, Power OK signals but since nobody ever seems to have a digital multimeter, I mention it for the record only!
I can't see it being the PSU itself or voltage fluctuations. I suppose it depends on the setup but power problems should turn off the supply and require cycling of the main breaker to reset.
What is the motherboard model? Can you locate the source of the click down to a device with a part number or a photo of it? A stethoscope would be good to trace the sound. Personally I would use my finger (after discharging static on the chassis) or a short plastic rod. One occasion where a grounding strap would be highly dangerous. At this point one has to assume the MB is probably done for, so there is little to lose.