Don't want to teach you how to suck eggs Colin, but try at least a couple of different cables. I've found with my Garmins that certain USB cables seem to charge fine but won't allow comms, others are fine.
This is a good call.
Also.. try a different USB port on your computer.
I have tried all 3 USB ports on my Win XP laptop and also tried it on my Win 10 desktop.
I took the device to a local phone shop and got them to plug it in to their PC using a lead of theirs, still no joy. That doesn't really prove anything though because I hadn't seen the same lead being used for data transfers on other devices. I gave up trying to get any sense from the lad in the shop because quite frankly he was too stoned to make much sense!
I have been trying different suggestions made by fellow sufferers online such as pressing and holding the menu button down when inserting the USB cable. I managed to get the same sequence of events to happen every time - if I have the My Computer window open I can see the 500 appear as a drive for a very short time and Windows makes that USB device detected noise. I can see a popup window saying something about files on the device, then an auto-play window pops up. Then windows makes the device disconnected noise and it goes back to charging.
It is very odd. The lead doesn't have an
intermittent fault because the above sequence happens every time no matter how I wiggle the connectors or flex the lead but maybe it is a bit borderline.
It's a bit ridiculous spending any more time messing about with this lead. I have just ordered a new one for 99p on
eBay,
including postage! I will leave the GPS alone until I get the new cable. I hope that works because I like the look of the 500 compared to my clunky old Etrex.