Well, I'm having to eat humble pie because I now have CC2 working under Windows 10 64-bit, but I'm not exactly sure why. By working I mean that in a campaign game, clicking on Continue no longer causes the game to crash. I've only tested it through two or three missions in the game but so far absolutely no crashes whereas before it would always crash.
So, what has changed. Well, I was on Windows 10 64-bit version 1703 and found that Windows update had been trying every day for over a month to upgrade me to 1709 (the Fall Creators Update), but kept failing (after re-downloading the upgrade every single time!!!!!). When I became aware of this issue I discovered that the error code was 0x8007001f - a rather generic code that gave me no real clue to what the problem was. I tried every "fix" I could find on the internet regarding this (and there is much snake oil online regarding fixes for this error code) but to no avail. I eventually found a clue to my problem here : http://www.zdnet.com/article/dont-move-your-windows-user-profiles-folder-to-another-drive
Like many people, my desktop has a relatively small SSD drive (C:) which I use for the operating system and program files and a HDD (D:) for everything else. Using guidance from websites like this, https://www.tenforums.com/tutorials/1964-move-users-folder-location-windows-10-a.html
(Method One), I had used sysprep during my last Windows 10 install to move all of my user profiles to my HDD. I believe it was this that prevented the 1703 to 1709 upgrade from working.
So, I bit the bullet and decided to do a clean install of Windows 10 64-bit 1709 but using a Microsoft supported method of moving most
of my user profile to my HDD (e.g. http://www.dummies.com/computers/operating-systems/windows-10/how-to-change-the-location-of-user-folders-in-windows-10
After two days of installing everything that I had previously installed on my PC (including the same video card driver version), I got round to reinstalling Close Combat 2. And this time when playing CC2 it no longer crashes. Interestingly, the ONLY compatibility setting that I have turned on is to run the program as an Administrator (without which the game cannot save progress). It doesn't
even need to be set to Windows XP mode or the like.
The only other change I made was to update my BIOS but I seriously doubt that made a difference here.
So was CC2 crashing between missions because of the version of Windows 10 (1703 vs. 1709), or the fact that I had used sysprep to move my entire user profile to my D: drive, or that my BIOS was 6 months out of date, or that my Windows 10 install had become corrupted somewhere? I really don't know the answer, but I suspect using sysprep to move my entire user profile was a major contributor to it.
Anyway, thought I'd post my experience here in case it helps someone else.
BTW - there's some excellent general advice on the Matrix forums by zakblood with regard to getting Close Combat working on Windows 10 (starts here : http://www.matrixgames.com/forums/fb.asp?m=4415444
One other thing, make sure that when you install CC2 that you run the setup program "as an Administrator".