Illustrator cs3 (mac) question

Arghh... !! now by trying changing the file>place link tick box i've changed my machine to create links to images when they are dragged into a document, but it doesn't seem to be a reversible process.....! Maybe the behaviour was just a glitch on my machine....

File -> Place, then there's a tick box for linking to the image or not, I imagine a drag and drop automates this process and will go with whichever setting was last used within the dialogue window.