Microsoft describe IIS as follows:
IIS for Windows® Server is a flexible, secure and manageable Web server for hosting anything on the Web. From media streaming to web applications.
Read more about IIS on Wikipedia.
Memory Validator provides a variety of tools on the IIS Tools menu to help you when working with IIS. See also Working with IIS.
IIS Tools may be disabled or not available if your computer does not have IIS installed.
If you need to install IIS, you may find this article on Setting up ISAPI (and ASP.Net) useful.
If at all possible:
•Run IIS on the same user account that you run the Memory Validator user interface
or
•Run Memory Validator on the same user account as IIS
•Don't run IIS in high isolation mode