i got an TM symbol instead of an @. What I do wrong?

I just starting up a new imac. When coming to registering I should make an email adress. Doing some trial and error to get the @ (now writing this on old computer that works) as I do on this computer (macbook) I dont get the @ . i get the tm (trademark) symbol. This makes it impossible to go further in the startup. What do I do wrong?