Good news! I rolled back my Windows machine to a restore point prior to the last WINDOWS Update on 8/16, and bingo, all is back to normal. I'm guessing there was something wrong with the last Windows update, or somehow the update did not install correctly on my machine. Thanks for all the help on troubleshooting the problem. Can anyone verify that rolling back the software fixed their network connection issue?  
Lost my internet connection to my Dell XPS 435t/9000 running Win7 (64) yesterday.  Unable to restore. No know configuration changes other than the regular weekly window update. My service provider is Verizon FIOS and all there stuff checks out. My iMAC and Dell Laptop connect fine through the same devices (router/modem/switch). The xps shows no hardware faults and all the wired connections are intact. Unable to ping router. Network Sharing interface shows good connections to switch and router by a bad connection between router and internet. Ran WIN7  network troubleshooter and it just told me to contact ISP. Rebooted machine several times but no joy. Any suggestions?        
Lost Wired FIOS Internet Connection on my Dell XPS 435t/9000 Unable to restore. 
Other home device connect fine.