thanks for your answer, I think you are correct saying it is a graphic driver problem ,I checked the updates and it had checked for updates only 10 mins earlier, reporting that everything was up to date. it is only the one usb socket not working. a couple of weeks ago I uninstalled a lot which had built up, and I had not used for a while. it now starts up from shutdown in less than a minute now, so I don't put it to sleep any more.