Decompiling CHM help files
Perhaps you are told that to edit a CHM file (Compiled HTML Help file, bearing
.chm file name extension) on Windows, you will need to download HTML Help Workshop. This is only partly true. Windows can decompile a CHM file and extract its contents. To do so, run the following command:
hh.exe -decompile <extracted> <filename.chm>
This will decompress all files embedded in <filename.chm> to <extracted> folder.
This method is tested and confirmed to work on Windows 8 Enterprise Edition (32-bit, IA-32, RTM, build 9200).
If you prefer a graphical user interface, 7-Zip opens CHM files as archives, allowing access to their content. A lot of people have 7-zip.