Follow this steps:

1.In Control Panel, Network Connections right click on Wireless Network Connection and select Properties.
2. Select Wireless Networks tab.
3. For each network listed that you don't recognize in Preferred Networks list and don't think it's trusted remove it from the list.
4.Click on the Advanced button.
5.Make sure that "Access Point (Infrastructure) networks only" is selected and "Automatically connect to non-preferred networks" is unchecked.