I was having issues with my study PC being sluggish. I have Xfinity internet using hard wired connections. I go into Xfinity web page and that loads fine. I click Support to get to their support page, and it opens it but sits there with the little ball going back and forth and back and forth on the page tab. It can sit for hours and never completes loading the page so I can click the speed test link. Works fine with MS Edge, works fine on my other PC in my shop on the same network, just this one PC. I've cleared browser history and cache and did a hard reboot. Nothing helps. It seems to be some setting or add on in Firefox. Started about the time the last update was pushed out.