original iphone no edge connection

could be a bad SIM. if you know someone else with an iPhone, try swapping SIMs (thats what the genius did with my SIM card, into his phone).

if not, then try, in this order:
-resetting network settings.
-restting the phone (home and sleep/wake buttons until the apple logo appears, ignoring the slide to power off screen)
-restore

I had the problem described in the original post, and resetting the phone resolved it. Many thanks for both the suggestions and the excellent instructions on the restore task.