When SBS 2008 was first released, it included a 120 day trial of both Live OneCare (Server) and Forefront Security for Exchange (FSE). Since then, Microsoft has announced they would be dropping support for Live OneCare. When installing SBS 2008, you are asked whether you wanted to install the 120 day trial of these two products. If you did select to install them, and now wish to uninstall them, the process is very easy.
From the SBS console, click on Control Panel > Programs and Features. Click to highlight Live OneCare and then click Uninstall. The uninstall process is very straightforward, and no rebooting of the server is required to uninstall Live OneCare.