Whenever I try to launch an mp3 file (by double clicking on it) i get an
error stating
"application has failed to start because NPPTools.dll can not be found".
When I click OK, an unknown mp4 player opens but it can't see/open the mp3
files.

I've located a download of the NPPTools.dll ZIP-file but when I try to
extract it I do not have access to allow installation into the Windows/System
directory where the instructions say to extract it.

1) If NPPTools.dll will fix my problem i need exact, step by step
instructions of what to do and how to grant permissions that allow me to
extract it into the proper Windows directory

2) If the missing NPPTools.dll is not the issue, what do I do?