As of this morning my PC (running Windows 7) has been unable to connect to my house's router, wired or wirelessly. With the cable plugged in, it tells me that "No connections are available". When I open up Network and Sharing Center, it gives me the message:
"The specified device does not exist as an installed service"
When I run troubleshooting on it, the problem it finds is:
""Local Area Connection" doesn't have a valid IP configuration"
Other devices (for instance, the windows 7 laptop I am currently using) are able to connect to the internet through the router without issue, wired and wirelessly. This means that the problem is related either to my computer, or the connection between the router and my computer.
Update: I created a new partition and installed Windows 7 to it again, so I can boot either copy. The new one accesses the internet just fine, which rules out problems with the network adapter or its drivers. The problem must therefore be related to that particular Windows install somehow...