|Found on the web...|
"note: the Windows Wireless Service won't start automatically if your Vista computer is a notebook and the notebook has a switch on it to toggle wifi on & off. The switch must be on for the wireless service to load automatically."
Some laptops have a button or custom key that toggles the wireless networking adapter's wireless feature (broadcast) on / off. In that case, there's probably an led that indicates whether it's on or off.
If you have that, is that toggled off while booting the computer ?
It's possible in theory that there's a bios setting regarding whether it's on or off by default while booting the computer as well.
If that doesn't help - see this - the service should be set to Automatic:
How do I start the Wireless/WLAN Zero Configuration?
I'm assumming you're using Windows' Wireless Zero utility.