If you have your wifi card setup and its talking to your router well, try doing a ping to your router. Then to any known sites that responds to a ping. www.hotmail.com will give you a timeout, so don't use that to test ping.
When its working, close IE if it was opened, and reopen it. It should just work. Only make sure it does not auto dial-up. Otherwise, it assumes a network stack is ready for use, and will try to use whichever is available.
let us know how it goes ya?
