In winxp home there are two start menu items ...
Windows Updates & Windows Catalog.
I am sorta thrown off by your description of which you are using, DHL.
One will take you to windows updates, and you will need to verify genuine winxp install these days to make it work properly.
The other is similar, taking you to a page that links you to a wide variety of download sites accessible by a search feature.
Both should work, if/only if the install was/is from a microsoft CD.
If your PC has windows preloaded from the factory, additional factors exist.
Again, your OS should be able to ID itself as "genuine", however.
I think the issue may be either related to the new ms identification procedures or possibly
you are being "re-directed" when using this (these) buttons. If that be the case, you probablyhave malware present doing the deed, and should post a HJT log for analysis.
Read the pinned topics here:
http://www.bleepingcomputer.com/forums/forum22.html