Problem:
Do not know how to uninstall before upgrading to a newer 
version since there was no uninstall utility provided with 
the previous version.


Solution:
IB V5.x
IB V4.x

To install a new version of InterBase on the server (when a 
previous version has been installed):

1.  Stop the current InterBase service by:
    a.  Clicking the Stop button in the Services Control Panel or
    b.  running " instsvc stop -z " at the DOS prompt.

2.  Remove the service from the services directory.  At the command 
     prompt, type:
         instsvc remove -z
    
3.  Remove the InterBas sub-key from the NT Registry.  At the 
     command prompt, type:
         instreg remove -z

4.  Install the new version.


Note:  	instsvc and instreg are executable files which reside in the bin directory of the
       	InterBase "home" directory:

	InterBase 5.0:  ..program filesinterbase corpinterbasebin
	InterBase 4.1:  ..program filesborlandintrbasebin
	InterBase 4.0:  ..ibserverbin

You should excute the files in the bin directory or include the bin directory's path in the
PATH environment variable.