Here are some popular fixes for networking issues:
1. Shut down your laptop.
2. Unplug the power to your router.
3. Unplug the power to your modem.
4. Wait at least 45 seconds.
5. Plug in the modem, and wait for it to come back online.
6. Plug in the router, and wait for it to come back online.
7. Turn on your laptop, and test your connection.
Reset the TCP/IP settings on your PC:
1. Go to your start screen/menu and type CMD.
2. Right click on the command prompt icon and chose Run as administrator.
3. In the window that opens type "netsh int ip reset resetlog.txt" without quotes, and press enter.
4. Restart your PC and test.
Reinstall the network adapter drivers:
1. Download the drivers from here but do not run them yet.
2. Go to your start screen/menu and type Device Manager.
3. Expand Network adapters.
4. Right click on the wireless/ethernet adapter and choose Uninstall.
5. Run the downloaded drivers from step 1.
6. Restart your PC and test.