That's a loaded question. There are so many things that can go wrong with setting up an Active Directory and securing site certificates that you can't answer it simply as "uninstall this". Did you ever create a site certificate with IIS Certificate Wizard? How many domain names are you using?
But here's some suggestions. Go to START, SETTINGS, CONTROL PANEL, Add/Remove Programs, Add/Remove Windows Components. Click Next, Remove Certificate Services and click finish.
If that doesn'tfix it, are you on SP2 for Windows 2000? If not, go to www.microsoft.com and search the knowledge base for Q282522. There is a list of fixes that SP2 (four pages in fact) handles and there were some problems with the DCPromo.