Installation of IOS7 has stuck my iPhone on AT&T screen - what's going on?

Question

After installing the latest IOS7  (it may have been 7. something) this morning (4 Oct 2013), the iPhone now only shows an AT&T screen, rather than the usual screen with all the icons.  The AT&T screen says: "Hello" and "slide to set up".  On sliding a numerical pad appears with the message "Enter Passcode".  I don't have a passcode for AT&T (and don't want one).  But the screen is stuck with AT&T, and I can't shift it, whether by pressing, pressing and holding, combination pressing, combination pressing and holding, or just switching off and on - it just comes back to AT&T.  So my iPhone is now useless.  Anyone encountered this, or got any ideas?

Answer 1

My original text explained what I meant - exactly what I saw, and had - I don't know how else one could describe it. The situation was unusual in that I had just arrived in USA from UK, and had also just (in USA) upgraded online to IOS7.  With an apparently useless phone I went in hope to the Apple Store in Georgetown, who very kindly sorted it out, quickly and efficiently - thanks Georgtown! The explanation was that my UK phone service provider (Vodafone) is apparently automatically switched to AT&T when I get here.  Coupled with that, the 4-digit PIN code I use to open my iPhone, which I thought was associated with the phone regardless of the service provider, was required by AT&T as their "passcode".  Bizarre - or at any rate, not self-evident to one brought up in the simpler world of the 1940s and 50s - but anyhow, it worked, and I've now got the icons - or at least a lot of them (but annoyingly, voice recording icon is no longer there).  Also annoyingly, I have to re-enter the passcode every time I re-open the screen, not just when it's shut down after 5 minutes; and I can't find the data roaming block in the new "Settings" area.  I suppose Apple Store will sort it out when I get back home, but meanwhile I'd better be careful how I use the phone while I'm here.