DVB-T Media Center Vista, no channels

Hi, just wondering if anyone can shed any light on why Media Center in Vista
is unable to find any channels at all using my DVB-T dongle? I've tried both
the antenna, and the aerial socket (which works fine with the STB) to no
avail. My computer recognises the dongle as an 'Intel CE9500 DVB-T Receiver'.
I bought it to use with Media Center :\ Haven't tried it with other software
because frankly I don't want to clutter the computer up by installing
unnecessary programs. Hoping someone may have had similar problems and might
be able to help??? )