OK I give up!!! After all of you have tried it successfully I decided I can not be so stubborn and I have to test this "smack" trick. What do you know - it works. HP - this is high tech at its best. Is it an extra hardware button you have hidden in the 6315 no one knows about? We are so proud of you!!! Anyways it works - so to summarize this nightmare: if you have a non working WiFi just because it does not turn off and it does not show the Wireless TAB in the WiFi Settings that means this is the solution for you. Hold the iPAQ with your strong hand and smack it on the back. Your WiFi will appear instantly.
Also, put a business card under the battery. It will constantly press the iPAQ and WiFi hopefully will always appear. Mine does.

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Bary.