MiniDisk and Soundcard

i tried to send sounds from my MiniDisk Aiwa to my PC, via the line-in minijack of my soundcard but i got no sounds in the speakers. i tried to plug my stereo-cd-player in the same way, and it works. if i plug my Minidisk in the line-in of my stereo-Cd-player, and the line-out of the stereo-cd-player to the line-in of the pc, i can hear sounds in the speakers of the stereo-cd-player but nothing in the speakers of my pc. ok it sounds confusing but how i can record sounds from my minidisk in my pc ?

cheers

laurent