Members deleting post

Is there anyway you can stop members from deleting there posts?
It only disrupts the follow on thread and to new members makes no sense.
Thanks

In the admin panel> go to the General tab>categories and forums>
Click the grey "forums permissions control" tab
find the forum name you want to modify and click on it.
there will be an option "delete it's own messages" untick it for members>
save.

I think you will have to go through and do it forum though.