Uninstalling SQL Server 2000, 2005 & 2008 on a Cluster
SQL 2000
If you have SQL 2000 in your network, you will need to follow a different set of instructions.
For uninstalling SQL 2000, refer to this article.
https://msdn2.microsoft.com/en-us/library/ms144255(SQL.90).aspx
Again, in case there are issues with the above, the steps listed in this article to manually remove SQL Server 2000 (standalone or cluster) will come in handy.
https://support.microsoft.com/default.aspx?scid=KB;%5bLN%5d;290991
SQL 2005
However, the approach is slightly different on a cluster. If you want to just remove a node from the cluster, you should follow the steps highlighted in this article.
https://msdn2.microsoft.com/en-us/library/ms191545(SQL.90).aspx
In case you totally want to remove the SQL virtual server on the cluster, the steps that you need to follow are listed in this article.
https://msdn2.microsoft.com/en-us/library/ms190438.aspx
Similarly, if the Add/Remove program interface cannot remove the clustered instance of SQL due to other issues, here is the article that will come in handy in such situations.
https://msdn2.microsoft.com/en-us/library/ms180973(SQL.90).aspx
SQL 2008