Vista Wireless Configuration and Troubleshooting
Step 10: Enabling the Radio
Note: Some wireless network cards do not support this option. If you do not have a Radio On/Off entry, skip directly to step 11.
Click on the Advanced tab. Click the entry for Radio On/Off. In the drop-down menu on the right, select On. Then, click OK. You will be returned to the Wireless Network Connection Properties window. Click OK in this window as well.