Norton online scan

Hi, I'm have trouble with a pop up that's on my internet. I do not have Norton, nor am I a virgin media customer, yet I open Microsoft edge (this is like an update for windows 10 instead of Internet explorer), look for a sight and this screen comes up saying action required. It has Norton Anti Virus in the corner. There's a box that comes up saying... This site says... WARNING: Virgin+Media Customer - Your Chrome browser and your PC may have critical security vulnerabilities. Call 020-3709-2205 (Toll-FREE) now for IMMEDIATE assistance. Please only call if the following date and time match: 8/31/2015 @12:48 Do I trust this? My mums been hacked before which is why I'm worried. And also because the box is 'very demanding' and won't let me take it down, minimise the screen, or do anything else except for stare at it! I've reset a couple of times and it doesn't come up until I go onto Microsoft edge. It doesn't do it with Google chrome. The screen has apparently identified Trojan.DealPly with a Critical risk and status as inflected. Then the same with something called SpyWare.bot. What do I do? Thank you for any advice!