Just to close this off, you indicated in another posting that you solved the problem.
For anyone else, if you are connecting the turntable through an amplifier, connect the line out of the amplifier to the line in of the sound card. You will probably need a cord adapter from phono to minijack, since your sound card probably has a minijack.
If you have an old turntable and you do not want to go through an amplifier, you need a pre-amp. Connection is the same as above.
If you have a USB connection from the turntable, see the tutorial in this forum: