If you only have dialup (and you do not want to wait for a CD from MS), first thing I'd have you check on is "how much time" on a single connection will your ISP allow you to stay connected? Find that out.
Then I'd suggest you make temporary use (you do not want it all the time, later) of a download utility --:
Internet Download Manager is a utility that is very helpful if you have a "must do" download and you need to overcome any possible "disconnect" due to timeout. I've used it with great success in the past. But I do not have it on all the time. Do not configure it to always be on; but rather use it "on demand".
Internet Download Manager home page.
www.internetdownloadmanager.com
IDM is ideal for downloading big files, whether you are on dialup or on broadband.
It will actually manage to resume a disconnect by doing a redial & resuming from where it was.
If you think you can manage the hefty download of the "full service pack 2" for XP, see this MS page
http://www.microsoft.com/downloads/...BE-3B8E-4F30-8245-9E368D3CDB5A&displaylang=en
If you have a non-English edition, pay attention to see the drop down list for languages on that page.
For tips to prepare for XP SP2 see this link at Aumha.org for
Windows XP SP2 - FAQs & Best Practices
http://forum.aumha.org/index.php?c=16