Tony brings up a solid point, you can accomplish this through GPO's within your network, but this will only work if everyone is on a domain that this particular server is a part of. Most likely this server in this case will be the domain controller.
As far as starting it automatically and pushing the updates out.. this all depends on what kind of antivirus you're using and how often virus definitions come out and how they come out. If you can find an antivirus solutions where the definition packages come out in .msi files or something similar, you can just use a regular GPO to push those out.
Jonas "Jackal" Lear
Serving the South Bay Since 1999