Connect to your wireless router then open the network status page for your wireless connection (Control Panel > Network Connections, double-click your wireless connection). Then open the Support tab and click Repair. Wait until Windows completes the entire repair process.
If 'repair' does not solve the problem, open the properties dialog for your wireless connection (Control Panel > Network Connections, right-click your wireless connection and click Properties). Now open the Wireless Networks tab. Under Preferred Networks, double-click your wireless network. Make sure that the option selected for Network Authentication and Data encryption match your router settings.
Finally, if none of the above solves the problem, try upgrading the driver for your wireless network adapter.
router make/model/firmware version? netbook make/model? NIC make/model/firmware version? need more info bro – BroScience – 2012-12-27T14:04:03.163