powering down the Touch and then rebooting it.
Restoring the iPod to the last backup, using iTunes.
Restore the iPod to factory defaults, again using iTunes. (all your settings will be lost)
Work from the top down
For further tips, take a look at the Apple site, http://support.apple.com/kb/HT1414 for how to's
Until yesterday, my ipod touch was receiving emails from four different accounts. But today I am not receiving anything and when I try to compose and send an email the little wheel just turns and turns. My ipod is right beside the router right now and still I can't receive or send. The only thing I can think of is that somehow the whole system got corrupted when a friend sent a very large zip file of photos, which downloaded onto my ipod and which I deleted. Could that be the reason? If so how do I fix things? Restore everything and re-setup up the email?
Does anyone have any other ideas as to what might be happening and how to fix it?