Siezing roles in Active Directory

Hi Guys,

I have started work at a new company recently moving back to corperate IT support from small business support. During my review of the companies servers I have found that the domain controller does not have all the AD roles.

There are 5 domain controllers in the organisation server1, server-1, server2, server3, server4. Both of the server 1 servers no longer exist in the domain. server2 appears to hold all the AD roles. However in Active Directory Users and computers the Infrastructure Master role comes up with an error (screen shot attached to see what I mean).

Is it ok for me to sieze the role following this knowledge base article.

http://support.microsoft.com/kb/255504

Also what would I need to do to remove the now non existant AD servers from the domain.

Thanks

Lloyd...
T