Uninstalling Oracle is not a daily event.

well, maybe if you are an oracle consultant of course.  But for me it was the first time, I am more an MSSQL person, with some Oracle knowledge. So, I will guide you through a very decent uninstall which is quite effective and save for the network.

First we stop all the Oracle services, next use the OUI to uninstall your Oracle product. You have to select all products that need to be removed. In our case, we just remove everything.

Second, we need to manually remove all the registry keys

HKEY_LOCAL_MACHINE\SOFTWARE
HKEY_LOCAL_MACHINE\SOFTWARE\Classes remove keys beginning with Ora/ORCL
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog\ApplicatioHKEY_LOCAL_MACHINE\SOFTWARE\ODBC remove all keys related with the "Oracle ODBC Driver"

Now we need to remove Oracle from your environment Variables and remove references under 'PATH'. e.g."I:\ora9idbcl\bin;I:\oradev6\BIN;D:\oracle\product\10.2.0\BIN"

Delete the oracle icons from StartMenu/Programs and ProgramFiles and remove any oracle related .ini files left behind in the Windows directory.

Then you reboot your computer.

Last steps are to remove the last bits of oracle left on your server, after this reboot you can start cleaning up or archive all Oracle files, backups etc.

Maybe you have a windows task running, in our case a task for a hotbackup has to be stopped and some analyze tasks.

Just run a search on 'ora' on the server to see if any vital oracle thingies have been left behind and you're done!