Still if Windows is unable to find any networks and your Wi-Fi is switched on, you need to find out if your wireless hardware is working properly.
To do this, click Start and then go to the Control Panel and double-click Network and Sharing Center. Then select Manage Wireless Connections, right-click the wireless connection you are trying to connect to, and select Enable.
If this doesn't work, click Start and type Device Manager. In Device Manager double-click on Network Adapters to expand it, and look for your wireless network adapter. If it is not there, make sure it is physically connected and check the installation. If it's a USB device try connecting it to some other free USB port. (This won’t work for internal USB wireless adapters.) A yellow exclamation mark in Device Manager means that it is not working properly and needs to be fixed. If there is a red X against the network adapter it means it has been disabled and you can enable it by right-clicking on it. If there isn't anything listed, you may need to fix the empty Device Manager.
In either case, you can try installing the latest drivers from the manufacturer’s website.
If that’s not the fix, contact the PCs manufacturer. You may have a device flaw that can’t be corrected in troubleshooting.