All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
Trying to change the evil is your duty because this is your own computer and it is not permissible for you to help someone else to commit sins on the pretext of being embarrassed. First of all, you have to delete those files as it was narrated by Abu Sa‘eed Al-Khudri, that the Prophet, sallallaahu ‘alayhi wa sallam, ordered the one who sees an evil to change it physically with his hand if he was able to do so. If he could not, he should change it by his tongue (by advising and/or condemning), and finally by (detesting it with) his heart, and he, sallallaahu ‘alayhi wa sallam, informed that this is the weakest level of faith. [Muslim]
You can change this by your hand since this is your own personal computer and you are responsible for it. If you did not do so you would be an accomplice in this sin. Allaah Says (what means): {And cooperate in righteousness and piety, but do not cooperate in sin and aggression.}[Quran 5:2]
Allaah Knows best.