1. USB sticks work just fine, Mouse / Keyboard work just fine, USB headset works just fine.
When i plug in the Oregon in the USB port it is just not detected. There is not even a notification in system tray that tells me an unknown device was detected. It worked fine for a few hours, then it just stopped. All I did during that period is to upgrade to 4.8 with Garmin Express and test the "Send to GPS" option. I have plugged / unplugged it a few more times without a problem after that, so it might not be the upgrade to blame. At one point... it no longer worked. There is no USB "image" displayed on the device when it is plugged in, it is as if it would not be plugged in at all. Sometimes I get the message that the external power was disconnected but those are few and far between.
2. By windows (both 7 and 10). Not sure what the browser has to do with it unless you are talking about the Garmin Communicator plugin, in which case, no, not working anymore.
3. Saving to SD is not a problem, I got a lot of options... External Card reader for PC, internal for Laptop, or the less clean way of inserting the SD in my tablet and then back in the GPS unit after the gpx was downloaded.
I have set the interface to both Serial and Spanner and nothing. I have hard reset it by holding the user and power buttons.
I have also now come across the http://garminoregon6xx.wikispaces.com/ page with a few more solutions which I need to have a go at.
It is frustrating that it is not working, but as long as I can still geocache with it and not just have an expensive paperweight, I'll be fine. Of-course it would be nice if I figure it out eventually and make it work as intended