Mouse, keyboard and monitor wont turn on

Hello,
Im having this really wierd error where my mouse, keyboard and monitor wont turn on. The strange thing is, on all other PC's my mouse and keyboard works fine and when I plug other things into the USB ports like a USB desk fan, it works but in the same place that my desk fan is plugged in, the mouse wont work, even though it will work if I plug it into a l;aptop or something.. I really dont know what's wrong. Its so wierd.