Has this ever happened to anyone else? My Curve was refusing to delete text messages so I removed the battery for a few seconds thinking it might re-boot it, but when I put the battery back in, SMS option has vanished from the phone altogether.
It has no savd messages or no facility anymore to create new messages. I have put the sim in another phone and that texts ok.
Can anyone help me please?

You are saying you did a battery pull and now you do not have the menu option to compose SMS? .... Do another battery pull, but not for a few seconds. Wait at least half of a minute. Do it again and wait a minute. See what happens.