@ VMatas

Didn't quite understand the comment. If your nuvi has entered in PC connection mode (you can see the PC icon on the screen) then it should be recognized as a Mass Storage Device. Try reinstalling the Garmin USB drivers:
[Only registered and activated users can see links. ]

Here is a cure firmware 4.10 I prepare for 37xx series. Hope it is helpful:
[Only registered and activated users can see links. ]

Normal FW 4.10:
[Only registered and activated users can see links. ]