You cannot open part .004 by itself. You must have all preceding parts ( .001 , .002 , .003 ) in the exact same folder. You then open the .001 file using 7-Zip or WinRAR, and it will automatically stitch the whole file back together. 2. Academic or Course Material Codes
Was this found as a on a storage drive or downloaded from the web?
While you gather more details, here are the two most likely explanations for this exact string: 1. A Split 7-Zip Compressed Archive
If you can tell me which of these you were looking for, I can provide a much more detailed breakdown or guide!