Ginger,
For the third part of your question, you do have many alternatives.
Unfortunately, 1 of those options is to re-deploy to the clients.
Basically what is happening, is all your clients use a file called, SYLINK.XML for communication with the server. Name, port, and key (if you will).
This is generated with the install of the server, so even a newly built server, with the same name and same IP will not have the same security key generated for a new install of SEPM.
Other options you have, replace the Sylink.XML file on each workstation with the new one generated from the newly installed server.
OR
If you have many clients, say too many to do this manually, follow the following link provided by Symantec
http://service1.symantec.com/support/ent-security.nsf/docid/2007082009543848