itunes / iphone5 will not show personel hotspot therefor unable to use as modem?

I have purchased a new iphone5 and had to upload the latest version of itunes to enable syc so that I could load data.

The "Personel Hotspot" did come up and I could use it as a modem alright.

Then did a reset on the phone as I didn't want the new phone to be a clone of the old phone.

Since then I have not been able to use the new iph5 as a Personel Hotspot.

Please Help Geoff.