This authentification pop up everytime I change page r open a page I dont' know the address 63.150.201.200

I have this authentification screen that pops up each time I open or change a web page.I don't know the address in my network. it's anoying as hell . not too mention dangerous. I have scan for virus and spyware . nada so if anyone can help please i'll apperciate it. Don't wnat to have to redo my computer .thank