I'm having the same problem, but it's not just outlook, it's all my office
products on my test computer. I have Vista Ultimate running Office 2007 and
I'm not able to modify excel worksheets, because most of the buttons are
disabled. As well as my outlook has new, reply, reply to all and forward all
greyed out.

What happens when you test account settings? What errors (exact message please) do you get?
I don't know where to find a utility to test account settings. I'm
connected to exchange and when new mail comes in I see it but I can't do
anything to it.