Another question for you :- sorry
If the USB ports aren't on the mobo, are they actually connected to the mobo. Some cases come with USB ports in them, but you have to get an additional cable to connect it to the mobo, if it has the facility.
If I remember right Basserho, you are using Win98se
Click on START | SETTINGS | CONTROL PANEL | SYSTEM then click on the DEVICE MANAGER TAB and see if they are recognised there ... there may be a yellow exclamation mark, and in the properties, it may tell you that you need the drivers installing .... just more for you to check, sorry