You run the self-extracting archive to extract the files. Older spreadsheet files tend to compress quite well, also. Document files, such as those used by Microsoft Word will not compress quite as well. If you open a DOC file with a plain text editor you will see many odd characters. This is because newer word processors and spreadsheet programs implement some light compression of their own.
Executable files tend to compress poorly.
Executable files are, by nature, designed to be as compact as possible to make them run faster and with less memory. Files that have already been compressed will compress very poorly. In fact, doing so may actually result in a larger file. It is inadvisable and of little gain to compress a file that has already been compressed. Click on New.