As I said above you need to join them.
copy and paste this to a text file.
Rename the file joiner.bat and double click it.
the joiner.bat must be in the same directory as the files when you do this.
save this to "joiner.bat" in the same folder of the files.
Code:
copy /b "Co_be_nhi_nhanh_1-_Upload_By_-_LengKeng.wmv.__a"+"Co_be_nhi_nhanh_1-_Upload_By_-_LengKeng.wmv.__b"+"Co_be_nhi_nhanh_1-_Upload_By_-_LengKeng.wmv.__c"+"Co_be_nhi_nhanh_1-_Upload_By_-_LengKeng.wmv.__d"+"Co_be_nhi_nhanh_1-_Upload_By_-_LengKeng.wmv.__e"+"Co_be_nhi_nhanh_1-_Upload_By_-_LengKeng.wmv.__f" /b ""Co_be_nhi_nhanh_1-_Upload_By_-_LengKeng.wmv"
this should join themfor you by binary option
or download the zip file with a finished joiner.bat file for you