Computer does not recognize UR12

On yesterday and the days before that, my UR12 was working perfectly. However, on this morning, my computer did not recognise my UR12, the USB signal light on the machine was continually blinking, I couldn’t find the device in Control Panel. I also tried to uninstall and re-install the software and to upgrade them through the download on, but the problem is still the same. I tried on other computers and received same results, what else could be wrong? :cry: :cry: :cry: