Uninstalling Cognos (upgrading to a newer version)

About this task

To date we have found that there is no upgrade for Cognos, i.e. Cognos recommend an uninstall and complete reinstall.

We have found that if you do not follow the following process when un-installing Cognos you may have issues starting the Cognos services.

To Uninstall Cognos(whatever the version is) click on Start -> Programs -> IBM Cognos 10 -> Uninstall IBM Cognos 10 -> Uninstall IBM Cognos 10. Select all in the wizard and follow the steps.
If the Cognos directory is still present on disk delete it manually
Uninstall IIS and reboot - then remove the directory C:\Inetpub otherwise you will get port conflicts as IIS remembers that the Cognos port was used previously.
Delete your JAVA_HOME environment variable - this forces the Cognos installer and runtime system to use the pre-packaged version of java that is shipped with Cognos.