Just revived the thread to let the helpers know what happened.

I gave up the idea of getting optical into the computer. It seems optical was something of a temperamental beast anyway, and I don't need that! It looked like being an expensive exercise. Old soundcards don't fit new motherboards.
I got a fairly respectable soundcard, but (possibly) the combination of new card and 64bit made 'LP Recorder', my preferred digitiser, also temperamental, so I had to buy an update of LP Recorder, as well.
Nowt's simple and cheap, is it?
One, or a combination of several, freeware digitisers that I was trying screwed my computer. Blue screen of death. If I was doing that again, I'd try, and then remove, one-at-a-time.
Thanks, guys. Chris.