Thanks Stormy.
Running the Msconfig Startup was one of the first things I did, and I was horrified to see the number of things on there, but I learned some time ago not to delete things based on guesswork, and I could only isolate a few of them as being genuinely unimportant. The other gobbledegook could have been anything.
Regardless, in the end after everything I did the laptop was running significantly faster and B1 was delighted, so it was probably a combination of everything.
Still curious about that Available Memory thing though.
Cheers,
Binos