How to open .001 files

How to open .001 files: .001, .002, .003, .004 etc. These files are "split" and contain separate components or parts of a program and need to be "joined" back together in order for the application to work, these parts will end up creating an ISO or Bin file. In other cases, the parts will end up making a directory that houses an installation directory for the program, or the entire program in ready to run form.
The file ending with .001 extension contains the information that will open and "join" the rest of the .002, .003, .003, .004 files together.

Use 7-Zip. 7-Zip is a well known Free archiving tool.

1. Download 7-Zip and launch 7z457.exe to install the program
2. Next, browse to your file ending with the .001 extension
3. Right click the file and choose 7-Zip > Extract Here:

4. The files should now be joined and have been extracted to the same directory that contains the .001-.009 parts.

If the program was originally an ISO, you may end up with a .bin file and a .cue file, you can then create a CD/DVD from the .bin file using your favorite CD/DVD creation software.