Using the Network troubleshooter in Windows 7
If that doesn’t help try to totally rebuild your network connections.
1. Go to the start and type Device Manager.
2. Select device manager from the Control Panel list.
3. In the Device Manager, select View>Show Hidden Devices.
If the Show Hidden devices is not present, do the following command from a command prompt Here’s how:
a) Go to start and type cmd.
b) Right click on cmd and select “Run as administrator”.
c) Type the following command and press enter. set devmgr_show_nonpresent_devices=1.
4. Locate the Network Adapters and remove all of them from the device manager by right clicking and selecting Uninstall.
5. Close the device manager.
Once this is done get the latest driver
updates for your network card by noting down the make and model from the device manager. Installing latest network card driver solves most of the networking issues. The best way to do this is by downloading from the Manufacturer’s website. Download the driver compatible with Windows 7.
Source> Windows 7 says I am not connected to a network and that connections are available, even though I am connected to a wireless connection with internet access