Using drugs is victimless, but given that a lot of drug manufacture and cultivation is directly linked to organized crime, buying drugs is only victimless if you know for a fact that your drugs are ethically grown, fair trade, etc. Which you don't.
I would agree that buying a computer who uses conflict minerals is not a victimless act. I find that a lot of what we do in modern society is not victimless even though we like to pretend it is.