Check the NIST standards. Having deployed them, a NIST compliant network/PC/server isn't very user friendly.
Here's a list of the check lists they have.
http://web.nvd.nist.gov/view/ncp/repository
You have to dig around some more at NIST to find their guides on securing a server/desktop. A nice way to learn. But heed my warning, once fully implemented, they are not easy to administer.