I’m checking my daughters garmin nuvi 255. Apparently she said the image was coming and going for a while and then it changed to “loading maps” turns off then repeats itself. I have connected the 255 to my computer (windows 7) but am unable to get it to recognise it, it just shows a computer on the 255 screen then repeats itself with loading maps. Have tried: 1.Reset button and hold for 20 seconds it comes up with a black dot in bottom left hand screen, then it repeats itself again. 2. When connected to computer it will not turn off. 3.With 255 disconnected from the computer , if I hold lower right hand corner of the screen while turning it on then screen comes up with a no or yes (to clear all data) which I have pressed but still the same .