Hi,
If I delete the one on the Desktop and the Mac has made a copy automatically in the folder it should be in... will that cause a problem then? I mean if it won't let me move it back... is it safe to delete it?
From what you say this desktop folder is just a copy, so there should be no problem deleting.
Oh... and what folder do you call Terminal? I can't see that one? Or do you mean the System's Folder?
No Apples OS X is built on a UNIX foundation and Terminal is a program included with all versions of OS X, you can find it in your application folder - Utilities folder. And this gives you a type stile interface that you can control or investigate things or areas of the Mac or do work etc.
Here is an example.
You could add a message of your choice to your Login window.
Warning it’s a sudo command which can be dangerous.
sudo defaults write /Library/Preferences/com.apple.loginwindow LoginwindowText "write your Message here"
And here is the command to put things back to normal.
sudo defaults write /Library/Preferences/com.apple.loginwindow LoginwindowText ""
But as you have never used terminal I would stay well away from it as the wrong command could cause many issues. Hope this helps.