Files with extension of 001, 002, 003 and so on are parts or splitted versions of a huge file. Also, many of such files are compressed to RAR or ZIP archives first before splitted. There are lots of questions about how to open such files and most of the time I read that the answer is to combine the files first–and oftentimes HJSplit is the free joiner application recommended to do this–and then extract the archive–the output of the files joining. Now, with a help of a certain tool, you can extract the complete version from the splitted files directly without having to join them first.
It’s 7-zip, a free extraction and compression program. You can extract the parts just like extracting standard files. Right-click on 001 file >> 7-zip >> Extract here.
This method has at least 3 advantages. It saves time since now you only have to do one task to get the complete file. It only needs a single program to do it. And, you only need to prepare smaller space for the extraction–if you combine the files first, you need to prepare space two times larger to cover both the combined and the extracted file.
7-zip is compatible with Windows 7, Vista, XP, 2008, 2003, 2000, NT, ME, and Windows 98. Visit the homepage to get the latest version.