The puxing 6-in-1 software download on the manufacturers website is supplied as a RAR file. To use the official download you have to extract the installer program from the rar file.To decompress a RAR file you need software such as 7-zip

The safest option is allways to get the software from the manufturers website, remember that some random software you found somewhere on the internet might steal your passwords or flood your computer with pop-up adverts.

I'm surprised at how many people can't figure out file archives, if you ask me they should go to their local library and sign up for a "computers for the terrifed" course alongside dodering 80 year old grannys being taught how to use a mouse and send email to their great grandchildren.

Anyway here is the .exe installer

Click on the file above, save it on your computer then run it.

when it asks for a serial number enter pxdz008

When you run that software it shows a box asking you to "select product",for my PX-777 I usually use "PX777/328 Ch128 +2tone"
I'm guessing that 2tone means DTMF,