How to turn on Airport on MacBook Pro

How to turn on Airport on MacBook Pro

"I am using MacBook Pro (Mac OS X 10.5). On the status bar, check I click the Wireless icon, it said 'Open Network Preferences'
And then in the Network Preference, I click 'AirPort' tab, the status said 'Inactive' But the 'Turn AirPort on' is disabled and the Network Name is disabled as well."