Also, OP, when you say, "use your mobile data", are you talking about using the cell phone itself to browse, or using your cell as a wifi hotspot, and using the same PC to use the cell's mobile data option, rather than your wifi router, on your wired ISP? Jack is probably right, it may just be down to a browser issue on the PC. My take on it, is that it could be security software on the PC, scanning what comes in on your internet connection. Maybe there's some settings (for "real-time scanning"), that need to be adjusted. What security software suite (if any) do you have installed on your PC, and what OS?