I would check your manual for your motherboard first, if you don't have it you should be able to get it from the manufacturers website.
Sometimes the front USB ports which connect to a header on the motherboard are only USB 1.1 and only the rear ones are USB 2.0. The manual should tell you if this is the case.
If you don't know what motherboard you have then download something like SIW and it should tell you. click here