Update your post to include full system hardware specs and OS information.
Make and model wireless network adapter?
Make and model router (or modem/router if combined)?
What error message is received when connection attempts fail?
Double check that only one network adapter is enabled. In your case only the wireless adapter should be enabled. Any wired network adapter should be disabled.
Manually download the applicable wireless network adapter's drivers via the manufacturer's website. Reinstall and reconfigure as applicable for your network.
Run "ipconfig /all'' (without quotes) via the Command Prompt. Post the results.