Last weekend, with advice from this site, I sorted out playing DVDs on my new laptop with Win 8.1, a day later I suddenly lost all internet access, after a friend had a look at it, it turned out it was MacAfee Virus Checker.
Because I hadn't taken up their offer to take up a year's subscription after a month's free trial, it blocked access to the internet, once I removed MacAfee completely I got Internet back and downloaded AVG. Definitely some sneaky moves go on these days. So, if you get a new computer with a month's free trial. Beware.