Microsoft has discontinued support for Windows XP Service Pack 2 systems; future updates/patches/support will require Service Pack 3 for the Windows XP operating system.
If the system is running Windows XP and is not already updated to Service Pack 3, be sure to read Microsoft's suggestions on how to prepare XP systems for Service Pack 3 installation. If any issues are experienced after installing Service Pack 3, first refer to this blog; it is run by a Microsoft Most Valuable Professional who is listing the most common issues following SP3 installation. Most other web resources seem to be getting their information from his blog post, but we certainly recommend a thorough web search should this blog not resolve any issues experienced.
Issues where Device Manager does not show any devices and/or Network Connections do not show any connections have also been reported. These issues relate to anti-virus programs possibly interfering with the installation of Service Pack 3; click here for a Microsoft Knowledge Base regarding this issue. A hotfix (KB953979) for this specific issue is available for download from both this article and the Microsoft Knowledge Base.
As of July 9th, 2008, Service Pack 3 should be available through automatic updates. To block the installation of Service Pack 3 through Automatic Updates, choose to not install it when notified of the update, or download the blocking tool (SPBlockerTools.EXE) from this article.
If none of the above options resolve any issues encountered with installing Service Pack 3, uninstall and roll back to Service Pack 2 if possible; otherwise a re-installation of the OS will be needed.