After you have created an AFSearch Index, click on [Settings | File Extensions] to define the file extenions you like to include for indexing. You can then use [Index | Add to Index] or [Index | Update Index] to index selected folder with the new file types.
In most cases, these converters are already installed in the default directory as provided with MS-Office installation -- which are usually at:
C:\Program Files\Common Files\Microsoft Shared\TEXTCONV\
The folder name might be different depending on your Windows version and language, e.g. it could be:
C:\Program Files\Fichiers communs\Microsoft Shared\TextConv
If you don't have the converter files, they are usually on your MS-OFFICE CDROM (search for files with .CNV extensions).
You can also download (FREE) Microsoft converter files from:
Please copy all the .CNV files to the TEXTCONV folder.