I managed to fix this problem by turning off my modem and leaving it off for more than 30 minutes. I read on another site rhat after a power outage, something happens to my assigned IP address that restricts my access to some dns addresses. I found that I could access all websites if I entered the full ip address but if I entered the url only about 50% of websites could be accessed. This problem affected all devices such as lap tops, mobile phones or my pc attached to the modem via wifi. Full shut down and restart of the modem and all attached devices for 5 or 10 minutes did not fix the problem. Only shutting down the modem and leaving it off for 30 minutes worked. Working fine now. ... View more