There is a Service that if it was turned off , it can disable all that stuff.
In control pannel | administrative tools | Computer management , Click on Services and applications, and then click on services.
Or WinKey-R and type services.msc
or in search just type services.msc and hit enter.
in there check for the 4 "network . . ." services. (I dont know the one that would have your symptoms yet)
fix this without reinstalling Windows 7
Yes, have a full Image backup of your operating system, that is created say weekly, and Recovered if nessisary outside of the operating system. A backup program like Acronis for example, that runs off of a CD or USB stick, and does not run that system, or depend or rely on that system.
I know this does not fix todays problem, but it will fix more problems in less time than anything in the system does. I have had the same problem your showing in XP once, spent some time redoing everything, doing discovery.
I Uninstalled the networking portions of the OS, Then Re-installed the networking portions, using add and remove windows programs (now called On and Off) and never figured it out. With windows 7 you really cant even remove networking components to reinstall them.
In 3 minutes I fixed it by booting to a CD, recovering my full image backup of the OS I had saved. Less time than it took me to write this. :-)
If you secure your Functional OS with an Image of the partition, Then store your important data on a seperate data disk or partition, away from the system. Then set your e-mail to stay on the server for a bit longer than usual, the loss from retracting the system back a week is minimal.
Somebody had to say it. Might as well be me.