Ensure you have all parts (001 through 050) in the same folder. Use a utility like 7-Zip or WinRAR. Only open the file ending in .001 to begin the extraction.
What to do if one of the .
This file was the pioneer, the keeper of the header information. It contained the essential instructions that told any computer exactly how many brothers and sisters it had—from .002 all the way to .050. Without this first file, the entire collection was just a jumble of digital noise, like a book missing its table of contents and first three chapters. 001-050.7z.001