Aye, here's the rub... I have tried 5-6 burning programs and cannot get the tracks onto the hard drive in any format from a cassette or vinyl record. Therefore I cannot convert to .wav etc. for burn to CD.
Audio is fine coming from computer speakers, so I am certain of line-in connection to computer is correct.
Turntable connected to Phono on Receiver -- Tape out from receiver to line-in on Diamond DT-588 soundcard.
I have no problem with getting audio tracks from a CD to the hard drive. What am I missing here?

Sound like you're mixer record settings are the problem:

http://www.audiotoolsdirect.com/faq/vinyl_1.shtml#09184897

In addition....

All I can think of is that you have your Soundcard default recording set to Microphone instead of Line-In.

Not an easy setting to track down as often the soundcard settings are seperate from the OS's own audio settings.