Don't know if this will help. Should be worth a look at the demo download.
http://www.findapp.com/fMgmt/PDetails.aspx?PID=7708
That is a very useful utility!
The problem was still not clear to me but something was going round in circles trying to run itself. 20 minutes on the phone to my mate Phil, IT Sage of EC2, revealed that what was looping was the hellspawn offspring of an union between Symantec and Microsoft.
Did not follow it all but in broad terms Microsoft have changed the encryption for Microsoft Update so it is Vista compliant and I had done that auto update. But some XP installations do not like it so you have to use the option in the Microsoft site update page to change it back to the old Windows Update.
But then something in the system still does not wholly match up with expectations of Symantec products issued before January 2007, which thinks you have an invalid Windows XP install. So you have to run FixWinXpCrypto.bat from the Symantec site.
Then it turns out that older Norton products still do not fare well these days so downloaded the Symantec uninstall tool and out went the original 2004 version. Still had one install left on a Norton Internet Security 2007 package and in it went.
Glory be, all is well. But I hope those collectively responsible in Symantec and Microsoft roast in the hottest fires of Hell!
Slight downside is that SpyBot is incompatible with Norton 2007. But SpyWare Doctor is and having loaded that in (cost a few $ but worth it) found 39 Spyware problems lurking that SpyBot had missed.
Ah, technology!