As you might have discovered, Microsoft has pulled their service packs from official website. What if you need to download them? archive.org to the rescue!
First you need to google for download links for the .EXE files of service packs installs for your language version. I needed Polish, so I found these:
Obviously, they are not working.
Then you need to visit archive.org and paste the links to their WayBack Machine. Browse through the calendar to find the link that is working. I got these:
Store your service packs in some safe place to save yourself looking for them again 🙂