
Daveppeters thanks for your reply!
To answer your questions:
The problem manifests itself regardless of the source media (vinyl or tape), although the manifestation (i.e. the strange sound) may be different. I have the tape deck and turntable connected to a graphic equalizer and receiver.
I thought that HD fragmentation could be an issue so I defragemented the original HD that came with the PC and still had the problem. I subsequently bought a new HD (Western Digital 40GB, 7200 RPM) last year and use that for storing the music .wav files...but I still have the problem.
To your last point, maybe I should try some different software. I also wondered whether it could be something in Windows that is causing the problem, but I have not been able to isolate it.
I remain stumped.
Regards,
brjblues