Well! After a lot of struggling and finding that removing the battery for 15 minutes WAS helping, I got into SAFE and copied over the user's docs and pst. Then got 'startup repair' to run but it finally declared it could not fix it.
Still getting a blank screen on 'normal' boot. Working on it.
The 'hidden' HP OS partition is there, but does anyone know how I run it from SAFE?
'Tis very odd - Home premium and it shows SP2
installed in SAFE? Trying to run CHKDSK at the moment.