Is a young man's informing his father that his computer is broken and that he got rid of it considered a punishable lie, knowing that he did so to rid himself of the habit of watching pornography and to conceal himself?

Lying is informing contrary to reality. What the questioner told his father about his computer is a forbidden lie, due to the narration by Asma bint Umays, elevated (to the Prophet): "Indeed, a lie is recorded as a lie until a small lie is recorded as a lie." The questioner's intention to conceal himself does not intercede for him, as he could have used allusions in his answer. The questioner must repent and seek forgiveness. If the device belonged to the father and he did not gift it to his son, then its price must be returned to him unless the father waives it.