I have a NUVI 250 (i think thats the model, im in work, its in the car =-) )
recently its started shouting at me to update it as its a year old and the camera positions/limits/maps need updating.
After a massive amount of time fiddling, theyre software finally admitted that my sat nav was plugged in. and then promptly BSOD'd my lappy. marvelously it then preseded to BSOD at startup untill after further fiddling i managed to uninstall it in safemode and now all seems fine (couple of months ago)
Satnavs still not updated, just making do atm. Probably get tomtom for my iphone instead!