In the past I've used VinylStudio, (which was found on the NAD website many moons ago). Now found here:-
http://www.alpinesoft.co.uk/VinylStudio/home.aspx
I trialed the demo version, loooong time ago, which I believe allowed you to sample a quiet passage where the software would 'listen' for clicks & pops. When you wanted to backup your record, it would subtract the noise from the whole recording.
Mark