Getting the files out of an installation file is fairly easy if you have the right tools.
A lot of people already have a tool to extract files from an exe: WinZip. If you aren't a fan of WinZip, try 7Zip can do it too, and it's free. You should have a decent zip program installed anyway. (Compressed folder is OK, but either of these programs offer a lot more options, including the ability extract files from some, but not all, installation packages (.exe).)
Universal Extractor is a free program that can extract files from Zip, MSI and other installation file formats. Right click on the file you want to extract and choose one of the UniExtract options.
Microsoft includes an application, Msiexec, with Windows that can be used for some but not all MSI files. It's command line only, no pretty GUI. (UniExtract can extract everything and is easier to use.)
Msiexec (command-line options) (Microsoft)
Tip: If you want to install certain Office updates (like an updated HOL file for Outlook that will work in multiple versions) but receive a message that you don't have the correct Office version, you can extract the needed file from the installation file. While you should never install hotfixes that are not specifically for your Office version, you can use this method for files that should work on similar versions. (There is no good reason why the Holiday update should be for only one software version.)