Mail not receiving emails

Recently my hard drive crashed and I had to have a new one installed. When I reinstalled the OS I was able to install Leopard. I setup my email in Mail and everything looks correct but it doesn't receive my emails. I can send emails just not get any. I never had this problem with Tiger. Does anyone know of a solution to this problem.

Thanks

Now in Mail/Preferences/Accounts/Account Information is there an entry for incoming mail server and outgoing mail server?

Yes there is a spot for the incoming server. I have that set to my domain name. When I did the Connection Doctor thing it connected to the server.

ISPs have differing entries there - check with your ISP - it might be pop2.isp.com or pop.isp.com or whatever