I am much indebted to both of You. Solving part one of this was thus far easier than I thought.
C'est humain, mais il faut y penser.... if you pardon my french ;-)
I had the Windows 7 HD on top of the boot sequence for convenience - since I was set on chosing HD at each startup, I simply hadn't counted on how Windows 7 would act. At first it worked fine, but after a few startups with the other HDD:s aboard Windows 7 suddenly realised that it was not alone anymore - and started interfering with a vengeance.
(I keep OSes on different HD:s whenever I can because that's "clean" and gives me space to play around a bit. Since I can chose what HD to boot from I simply don't need the Boot Manager Screen.
If I needed one, I'd pick Easy BCD, that worked well when I dualbooted laptops and
had to make do with a single HDD.) And no, there were no previous dual boots on this machine.
So I just 'demoted' the win 7 HD to number 3 on the HDgroup in the bootlist, and now I can start XP and Debian with no interference.
But whenever I start with the Windows 7 HDD I still get the BMS.
Of course I can solve that by going into the msconfig and change the timeout from 30 to 0 seconds.
But I can't remove the other entries because they're not there (in msconfig) - there is only the Windows 7 option - as should be. That's logical, isn't it? After all all OSes were installed separately with the other HD:s disconnected.
It's only the BMS (when I start with the Windows 7 HD) that behaves illogically and makes a fuss about the other OSes.
So, if I understand this correctly - if I want to do this the
very hard way (instead of just resetting the timeout as I said above) I should boot up Windows 7, foray into the BCDedit (thanks for the link to the GUI variety) - not msconfig - and delete the XP and linux options?
And that will
not affect their ability to start (because they reside on their own HDDs and are in no way dependent on the Windows 7 BM) - it will only get the Windows 7 BM to stop meddling.
Correct?
Wow. Thanks a ginormous lot, guys (er, fellow sentinent beings of any gender to be PC)! Windows 7 certainly works/'thinks' differently from XP - and I'm a late convert (I threw out Vista ASAP).
I'm actually beginning to enjoy this now...

