install and re-install

In order to response to my question #203696,
Yesterday, I tried to re-install a BeatBox, but I unable to see a menu list at the "Top Left" side.
So, I used a "Gear" symbol, Preferences, and pointed where the Library are ... NTFS_external_HDD/Music/Lossy ... & it scan my library
But after 5 minutes, the electricity is down for 2~3 minutes ... when the electricity is back, I've tried to re-scan the library through Left "Gear" symbol > Preferences > and pointed my library ... but no response at all.
So, I repeat the above action ... and know that the library is default's library (/home/***/music) ... not mine.
Repeated on and on and on ... but nothing is change. So, I tried to:

$ sudo apt-get remove --purge beatbox

Clear all the Janitor with Ubuntu Tweak, re-start the lappie, open the terminal, type:

$ sudo apt-get update
$ sudo apt-get install beatbox

But the installed beatbox still contains a library which not yet finished scan.
Why?