Q: no service

Have Itunes restore it. Connect your iphone to a computer that has an internet connection and see if there are carrier update available. then click on the image in the iphone button to get to summary. Then click restore.

there maybe something here that may help

http://support.apple.com/kb/TS4148

similar type of issue

Read here:

http://support.apple.com/kb/ts4429

If you've done everything in that support article, make an appointment at any Apple store.

replace the sim card?

Then make an appointment at any Apple store, there are no more user troubleshooting steps available.