You don't *really* need to read this but if you are working with, or think you may work with, Reporting Services this article might save your life. Ok that is an exaggeration but it could certainly save you some heartache. Or stress. And as stress is a growing threat to our mortality actually it could save your life!
The kb article below relates to a failed installation of Reporting Services. I have found that this article addresses problems that occur with a variety of failed installations.
Scenario 1 is that the product installs but the Report Server does not activate. You attempt to start it manually but this fails.
Scenario 2 is that the installation does not complete with an error and you receive a 1603 or a 25619 error message and the installation then rolls back.
This can happy for many reasons. the Reporting Services application is tightly integrated with the Windows environment and sub system. An issue with the IWAM_computername account or an older version of .NET framework being present can all contribute.
In my case I was lucky enough to have the install thwarted by what was labelled by Microsoft as a 'as yet undetermined error'!
The workaround which has solved these issues involves running setup from a command line and telling the installation not to create the virtual directories and then manually creating these afterwards.
It looks a little daunting at first but it is quite straightforward. The following kb article contains all the information you should need.