I want to create an installation disc for Microsoft Windows XP Professional with Service Pack 1.

Service Pack 2 for Windows XP is not to be applied.

How would I go about downloading all the relevant update patches for Windows XP Professional with Service Pack 1?

You could go to http://www.microsoft.com/technet/security/current.aspx

and do a search.

Great I had lost the location of the TechNet search page. Thanks.

Also, it seems that "Show only bulletins that contain updates that have not been replaced by a more recent update." ("CHECK") does not fuction correctly. Some updates are displayed that are flaged with "The update for the selected product has been replaced by the update in the following bulletin(s):" ("REPLACED") when CHECK is checked.

If CHECK is checked, would the results less items marked REPLACED, represent all the correct updates?

You could try installing xp sp1 and running mbsa, microsoft baseline security analyzer to get a list of needed updates.

I think ms are pushing post sp2 updates only through windows update though. Depends on your usage/needs but could bring more grief than it's worth, security wise.

tbs

Forgive me if this sounds curt, but SP2 was released over 28 months ago and MS has pulled the plug on all older versions.

So like tbs said...best of luck, really.