Ok, my helpful new best friends... Here's what happened next....
The only HDD plugged in is the Vista OS drive.
I went into the BIOS and changed the boot order so that boot from disc is first.
So...
Up comes the install screen, I choose English and click next.
Below 'install' is 'repair', so I click that.
It shows me the Vista installation is the only OS it's detected so again I click next.
It then gives me various options, the first being 'startup repair' to repair any problems preventing windows from starting.
I click that, it does whatever it does, then tells me to restart, so I do.
Again I get 'press any key to boot from disc', this time I let that time out, but instead of windows booting as hoped it then starts scrolling down the screen with
Press F10 For Recovery
I do this, and immediately get the old
NTLDR is missing
Press Crrl+Alt+del to restart
Anything else I can try??
And thanks again all....