Alot of the vendor software in our industry (utility provider) seems to come with a contingency that it will do the job accordingly, if we agree to paying for a support contract. Seems that most vendors are unwilling to take a risk on their code, without securing your cash upfront. In some cases, the product may not do the job it was meant for, but lines like
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, [blah blah blah].
are designed to protect the vendor from situations where their product just plain does not work in an environment. Its a lot easier than saying
We guarantee that our product will address this exact issue, at this exact time, if you are located in this time zone, and your infrastructure is setup like.....
It allows them to charge exorbitant contracts in the business environment. On the home user side, it allows software vendors to not be responsible for users incorrectly purchasing software, and attempting to install and register, and then taking action against the company if their system will not run it.
So to get to the point, I have not seen a valid use of a warranty for software, that was not dependent on a service contract. Not saying they do not exist, just that I have yet to see them.