Trade Name, Trademark, Service Mark

What is the difference between a Trade Name, Trademark, and a Service Mark?
What are the trademark and service mark classifications?
What are specimens for trademarks and service marks?
Does registering my trade name with the Department mean that I own that trade name?
If registering my trade name does not give me ownership rights, why should I bother with registering the name at all?
Will the Department check to make sure that no one else is using the same name that I want to use?
If more than one person has chosen the same (or very similar) trade name, who has ownership of the name?
If I have checked and found no use of the name I want in the State but have also found a registration for that name, can I get the Department to revoke the earlier registration?
If I want to register a trade name that I have been using for a while and find that someone else has already registered that name, can I get that registration revoked?
If my registration is accepted, how long is that registration valid?
Is there a difference between a corporate name and a trade name?