It's years since I ran a windows machine but try this.
Run the network troubleshooter and check what the result is. To open network troubleshooter follow the links given below.
http://windows.microsoft.com/en-US/windows7/Using-the-Network-troubleshooter-in-Windows-7
http://windows.microsoft.com/en-US/windows7/Why-can-t-I-connect-to-a-network
If the troubleshooter does not help, would suggest you to use the below mentioned steps and check -
a) Click Start.
b) Type ‘cmd’ in the Start Search box, and then press ENTER
c) At the command prompt, type the following command, and then press ENTER:
ipconfig /all (there is a space between ipconfig and /)
the ipconfig /all command displays Windows TCP/IP settings for all your network adapters.
d) If your IP address for your Local Area Connection is either 0.0.0.0 or 169.x.x.x (where x is any number), then your computer is not getting an IP address from the router.
If that is the case, try this:
a. ipconfig /release in the command prompt and press ENTER
b. ipconfig /renew in the command prompt and press ENTER
e) Test it again by typing ipconfig /all to see what the address is?
That's as much help as I can give re MS Win, and that's pushing it as the old grey cells are what they used to be.