Question : Force removal of exchange

I want to remove an exchange server from system manager, I can no longer do it through locall on the exchange box through Add remove program, as the box has already been disposed of

Answer : Force removal of exchange

You can remove the stale server from AD using ADSIEDIT

Open ADSI Edit.

Expand each of the following items: Configuration Container
CN=Configuration, DC=Domain_Name,DC=com
CN=Services
CN=Microsoft Exchange
CN=Your_Organization_Name
CN=Administrative Groups
CN=Your_Administrative_Group_Name
CN=Servers

Right-click the Exchange 2003 server object which you want to delete, and then click Delete.

Reference : http://support.microsoft.com/kb/833396

Make sure that you have reassigned the responsibility (like OAB RUS) of the old server to any other server.