I have a Windows Server 2003 SP1 machine that was service packed to SP2. If I now add additional components such as IIS to this machine, do I need to reinstall SP2?
If Windows handles this for me, how does it do so?
No, it's not be necessary in Windows Server 2000 and later.
When you install a service pack the
The source location is stored in the following registry key:
See this Microsoft support article: Not Necessary to Reinstall Windows 2000 Service Packs After System State Changes
You can use the windows update in custom mode to see if there are any updates after installing the new component. It's scan should detect everything installed and make the recommendations for you.