unreg.bat should be in the installation folder of BSPlayer. (Have you used Windows' Search-possibility?)
P.S. Did your new installation overwrite the earlier, or do you now have two BSPlayer installations at different locations?
Further:
:!:
When using K-lite please make sure to also use its possibility to select and/or deselect and do not install everything from it (it may cause conflicts and thus problems!!)
The art is... to restrict yourselves in your drifts!
:!:
Preferably download BSPlayer directly from its creator:
http://www.bsplayer.org/html/download.php
(or alternatively from
http://www.dvd.box.sk/index.php?pid=...=info&rid=7553)