BleepingComputer.com: USB TV tuner dongles not recognised

This is a wild shot in the dark - I do not know whether anyone can advise me as it is not exactly computer related. I recently purchased a new desktop replacement laptop with Windows Media Centre installed and I hoped to be able to use this feature to view and save live TV progs. to the laptop. I have tried 3 different TV tuners, none of which have been recognised by my computer. I do not know if the usb is not sensitive enough and have tried each of the 3 usb ports without any success. These dongles came with small under-powered aerials so I purchased a better amplified aerial for the tuner - still no luck. Just to confirm whether or not the aerial was faulty, I plugged it into the nearest TV, in place of its normal aerial and it worked fine with no loss of picture quality. The roof aerial, when plugged into the TV dongle, picked up and saved 112 digital TV and radio stations, so that bit worked, the problem is the unresponsive TV dongles. Does anyone have any ideas about this?

Many thanks