Fault with usb digital tv device (peak brand and i live in the uk)?

Had a peak brand usb digital tv device givien to me for xmas. cannot get the product to work. background. my computer is a laptop hp model no: ze2205ea (2yrs old) running windows xp service pack2. software loaded ok to support digital tv device ask the item to scan for channels and it cant find any at all have used aerial supplied and also high gain out door digital tv aerial which i know supplies an excellent picture to the tv. my son as tried this usb device on is desk top computer and can only get it to work by taking out of its plastic case then it works ok, (put the case back on and it wont work) will not work on my laptop with case on or off. any computer xperts out there can help.
Answer
Simply try your main tv aerial in the device and see what happens. there should be an adapter supplied with the device t allow you to do this.the reason for this is that the little aerial that comes with usb tv devices are generally of little or no use in most home environments. your son appears to have got lucky and found signal whereas you have not. this depends on the orientation of the aerial wit respect to the signal source, and also whether you are near a window (nice) or a thick or reiforced wall (bad).anyway try your main aerial, i am sure the device is not faulty.