Thanks! It now seems that my Firefox browser was corrupted in some way. I uninstalled it then reinstalled it and it works much faster now. I'm going to call it "solved" at this point.
I have a Win 10 machine with no problems. My Win7 machine recently has become extremely slow in accessing the network, clocking in at about 1KB/s. I stopped all services I thought were unnecessary, ran virus and malware detection software then switched these off. Network Sharing Center says...