I can no longer get my desktop to connect to the network. Everything else connects fine; laptop, cell phones, game consoles, etc. The issue started after I did a manual reboot of the computer to try and fix an issue I was having with a game that kept crashing. Before the reboot, it was business as usual, but after the reboot, it refuses to connect. The diag tool says the modem is experiencing connectivity issues, but I've tried resetting both the router and modem, a direct connection to the modem, a wireless adaptor I have from work, and nothing is working. I can't even access the router through the IP address.
Additionally, I can't see anything on the network from the desktop (the router doesn't even show up under Network); however, I can go into the McAfee suite and look at the network map from there, and it shows the router, and everything else that's currently connected to the network. I've ran both a quick and a full computer scan and zero issues came up on that front.
I had the exact same problem. I posted a similar thread here and looked two posts down and saw yours. Yup, it was McAfee. As soon as I uninstalled it I got my internet connection back. Going to see ifothers found out what it was before I re--install McAfee.