Download latest PSPad 4.5.7 from PSpad developer forum If you registered file types in PSPad program settings / File association, you need reregister it. If you did it via operating system do it again.
In any case you can use right mouse / Open in PSpad -- <http://forum.pspad.com/read.php?2,58025,58028> PSPad freeware editor http://www.pspad.com
