I have been looking all over for a solution to this problem, but I have yet to find one. It all started when one day I booted up my computer and out of nowhere I couldn't connect to the Internet. I restarted my PC, hoping for a quick fix, but instead what happened is that my computer wouldn't boot up anymore. Every time it tried to boot up, it showed a blue screen of death for a brief moment shortly after the Windows logo starts forming and turned off. What fixed this problem is using the "Last known good configuration" setting on the Advanced Boot Options Menu. However, even though the computer could boot up now, it still showed that my network is unidentified and it wouldn't connect to the Internet. Strangely, my other PC that is connected to this network had a Internet connection, and Wi-Fi worked for my Android phones. However, I noticed that the connection was very unusually slow for these devices for a while, but after a day or so the connection speed was normal again. I first thought that a virus could have caused this, especially considering that the CPU and memory usage for this PC was extremely high even though nothing was running. I used a flash drive to bring over some software to the PC: rKill, MalwareBytes, ADWCleaner. Rkill didn't find anything, MalwareBytes didn't find anything (I checked the "scan for rootkits" option), but ADWCleaner found some PUPs and deleted them. CPU and memory usage seems fine after this, however there was still no connection to the Internet. What I did next was:
Use the NetAdapter Repair tool, which didn't help.
Replace my network adapter to one which I know was working, didn't help.
Connect a USB wireless network adapter, install the drivers for it, and it could connect to my Wi-Fi network, but it still showed up as unidentified, so I couldn't connect to the Internet.
Reinstalled drivers for my Ethernet network adapter.
Tried connecting the Ethernet cable to different router ports, didn't help.
Connecting the Ethernet cable directly to the modem, didn't help.
Tried a different Ethernet cable, didn't help.
Tried disabling and then enabling Local Area Connection, didn't help.
Tried ipconfig /release, which results in this: "An error occured while releasing interface Local Area Connection : An adress has not yet been associated with the network endpoint."
Tried ipconfig /renew, which results in this: "An error occured while releasing interface Local Area Connection : A socket operation encountered a dead network."
Tried netsh winsock reset and netsh int ip reset, both were successful, but after restarting the computer the problem still remains.
Tried ipconfig /flushdns, which was successful but the problem remains.