Go to your device manager, Click Network adapters. You should have your wireless and non wireless network adapters listed. Uninstall the wireless drivers and then reinstall them.
If you originally were using the wireless adapter's drivers that windows 7 provided then try to look for them on the manufactures website instead and use those drivers during your re-installation.
If problem persist please list the make and model of wireless adapter along with drivers your using. Motherboard too. Thanks.