I ran into a somewhat similar situation, except I was not fixing someone's computer. At a place where I used to work there were a couple of people who had permission to use the computers after working hours to play games. One morning I came into work and printed something on the communal printer. When I went to get my document, I found downloaded printed porn of the most extreme woman-hating variety. Not just pictures of naked ladies, rape, torture and murder, including a link to a site where one can buy what were billed as "woman torture movies".
So far as I know this was not illegal material; so far as I know, the women in the films/pics were not ACTUALLY being raped, tortured and murdered and were over 18. But it sure creeped me out that at least one of my coworkers got off on this shit.
I took them right to the HR manager. I can't say she handled it great. She said that anyone who used the workplace computers for this would be fired (no argument) but justified her statement on the grounds that "there are ladies here". While it's true that as a woman my reaction might be more visceral than a man's, there are also plenty of men, not necessarily on this board, who find the idea of porn generally and rape/torture/murder porn totally objectionable.