So you've Enabled Internet sharing from your windows phone using Bluetooth. You have also paired with your laptop.
But, still, no internet. Why not? Have you connected via the Access Point?
When you pair over Bluetooth, you create a "point of access" to use the internet of your windows phone.
If you have the bluetooth icon in your taskbar at the bottom right of your screen, skip to the next step. If not, you need to enable it to gain access to your computers bluetooth menu.
Go to Settings on your PC. Go to Devices. Go to Bluetooth. See "More bluetooth options" under related settings. Open this and make sure "Show the bluetooth icon in the notification area" (which is the bottom right part of your taskbar that we talked about earlier) is ticked so you can now access it FROM your taskbar.
Click the bluetooth icon (or reveal it first from the hidden icons shortcut up arrow) and go to join a personal area network.
You should see your windows phone there. Right click -> Connect using -> Access point.
DONE! YOU SHOULD HAVE THE INTERWEBS! WELL DONE!
If it is not working its probably because your phone's internet network is too slow - reason being is that when I was connected on 2G, I had no internet access until I had 3G signal. Open your Network and Sharing centre to confirm whether the network you are now connected to has internet connection or not.