You can resolve most issues with your iPad by doing a forced reboot.
Examples of what will be resolved:
If your iPad is frozen
If your mails are not opening
If your Apps are not opening
If you are unable to connect to the internet even with the correct password
Doing a forced reboot will do no harm to your iPad therefore for any such issues you must try rebooting it before Restoring it.
Press and hold the iPad’s sleep wake and Home Button simultaneously until you see the white Apple logo. When you see this, you can release the buttons. Once this is done check if the issue has been resolved.