your SSB is probably connected to the laptop via pactor and seriell to usb converter.
What happens when you plug and unplug the usb cable at the laptop?
We experienced a leak/the lamp on - although the SSB has an isolation transformer. Difficult to explain (there is something "funny" with the usb shield) but we fixed it with a seriell optocoupler. It works like a galvanic seperation and seperates the computer from the SSB. You can get them as a seriell plug with male on one and female on the other side, so it fits between the seriell cable (from the SSB) and the "seriell to usb" converter cable from the computer.
Walter (Noa, SM2K436)