Good question, dhn. There have been Blue & Me systems built on both Nav2 and Nav3 platforms. The very earliest were actually built on the GO750 base. The rest have been Nav3 units. It will depend upon the age of the device. Units with serial numbers that start with "WI" are the Nav2 units. Those starting with TN, TI, TH, TM or TG are Nav3 units. Either way, the reset will be 20 second hold of the power button.
@zelroy
What are the first 2 characters of the serial number on your unit?
Does your device behave normally when operating in the vehicle? In other words, does the screen fail to produce a picture ONLY when you connect it to the computer for updates?
As suggested, try a reset of the unit. Hold the power button down for 20 seconds until you hear the drums start to sound, and release immediately at that point.