If you download a file that split into several parts, and ending in 001 and others, you need the application to make these files into a single unit in advance, the software called hjsplit,
you can download the software below :
LINK
Password : http://gilagamepc.blogspot.com
After you download the software, open the software and then click JOIN.
Remember before, collect first that you've downloaded files in one folder.
After you click the join button, then you will be asked to enter a file.
When you click on the input file, find the folder where you store files that you download, if you have found the file you mean, usually appear only files that have a .001.
Select the file that, after that you just select which output you want, and last just press the start button, wait until the merger is completed.
How To Install from apart file extension .rar
First collect separate files in one folder
then double click the first .rar file