Thank you for your quick responses.
I haven't locked myself in

I do have the admin's password, it's just that it's easier, for instance, to install programs straight form the limited user.
I'll check the UAC and I'll get back to you.
I found it curious that this happened, because at home I created a user called 'admin' with privileged access and I've limited my own user and it works just fine (I think I've already said that

).