Q: Warning! I'm not very iPad savvy. today I took my husband's iPad to the apple store & it was reset.  all looked good. now (at home) in the top left handcorner it says 'no service'.  what do I need to do? please!

These instructions say iPhone, but ignore that.  Everywhere it says iPhone, think iPad

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

Symptoms

Your iPhone may have one of these symptoms:

• iPhone displays "No Service" or "Searching" in an area of good coverage
• iPhone doesn't regain service when returning to an area of coverage

Resolution

If you encounter either of the above symptoms on your iPhone, follow these steps to attempt to resolve the issue. Test after each step.

1. Toggle airplane mode: Tap Settings > Enable Airplane Mode, wait five seconds, then turn off airplane mode.
2. Turn iPhone off and then on again.
3. Remove the SIM card and verify that it's a valid, carrier-manufactured SIM. Also verify that it isn't damaged, worn, or modified. Then reinsert it.
4. Check for a carrier-settings update. Connect to a Wi-Fi network. Then tap Settings > General > About. If an update is available, iOS will ask you if you want to install it. If Wi-Fi isn't available, connect your device to iTunes.
5. Update your iPhone to the latest version of iOS.
6. Reset network settings by tapping Settings > General > Reset > Reset Network Settings. This will reset all network settings, including Bluetooth pairing records, Wi-Fi passwords, VPN, and APN settings.
7. Restore the iPhone.

If you're outside the United States, please also follow these steps:

1. Go to Settings > Carrier > Automatic.
   If the phone registers any carrier network, Settings > Carrier will be present.
2. If the Carrier option is missing in Settings and you're outside of the Unites States, please contact Apple for support and service options.
3. Set the option for Automatic to off.
   A list of potentially available carriers appears after about two minutes. If the device is locked to a carrier, it may connect only to the carrier network to which it is locked. If the device displays carrier networks, then the device is working as expected.
4. Set Settings > Carrier > Automatic back to on.

If you're still experiencing No Service issues, contact your carrier to check for any network or account issues that could cause these symptoms.

"No Service" means that the iPad cannot connect to a cellur signal.  Try turning cellular data off, and use WiFi to see if that works.

If the iPad is not receiving cellular service, you might need to contact the carrier that provides the service.

Turn off Cellular Data

Settings>Cellular Data>Off

Yes, it's the same thing.