It happened suddenly and I don't know how to fix it. Rebooting didn't help.
You might try a factory reset, which will delete all data and put the watch back to day 1 settings. This is assuming that it doesn't shut down while you're trying to do the reset. If no luck, might be a stuck key or some other hardware issue. In which case, contacting Garmin via phone or chat would be a good option - support.garmin.com/.../
Same issue for me too. I've removed all the widgets one by one to see if that cures it but it doesn't - the watch just restarts and all the widgets that were previously removed are back again. I've contacted Garmin support a couple of days ago - still waiting for them to reply
Oh really, I hadn't thought of removing the widgets. The watch seems to be very sensitive. I only bought it at the start of January so I will speak to the retailer about this issue. I tried to update the software but it didn't fix the issue. Let me know what Garmin support say.