|When it comes to lacking a sense of humor, your co-workers are at the top of the list. Their practical joke was neither practical nor a joke. They must have forgotten one of the key elements of humor: it is supposed to be funny.|
Their action is better described as being a dirty trick. It is mean spirited, malicious, and hurtful.
You certainly have a right to be upset, but frankly it is not worth the effort. In fact, if you continue stewing over these co-workers, all you are doing is letting their pathetic joke continue.
You expressed your disapproval to them, and hopefully you indicated that this type of nonsense has to stop. In addition, if you did not discuss the incident with management, you should think about doing so now, and definitely do so if there is a repeat performance. Management is not amused by employees who secretly enter a co-worker's computer and start moving files around as some sort of joke. In fact, employees who do this may find that they are the ones who get moved around.