I'll get round to doing that Boot In Safe Mode plus Networking some time tonight or tomorrow morning Fax.
Meanwhile, I've just downloaded and run Superantispyware (**** name btw!) and am now running Emsisoft Emergency Kit. Just some billy-basic tracking cookies found so far.
I will update the post above in due course.
However, what I find interesting is this: Every program already installed on my PC, plus every program that I've downloaded and installed over the past few weeks since this ZASS stalling-at-scan issue started, has run perfectly - that's each and every program, with the exception of ZASS.
And that to me speaks volumes, frankly.
Plus, WinPatrol & Spywareblaster & Spybot S&D sit quite happily alongside ZASS 10.0.250.000 on two other single-HD PCs just now - so it's probably not that.
To answer your question: What kind of optimisation you allowed by those HD utilities? Did you defrag your boot sectors? Yes - I did optimise the Boot Sectors, and the Page File System as well...but not until WAY after ZASS 10.0.250.000 stopped working.
And since then, at the risk of repeating myself, every other program - either previously installed or downloaded & installed afterwards, has worked perfectly - again with the exception of ZASS.
So - until proved otherwise, I'm still gunning for the DAT version being the culprit.