[quote="seanhutch"]k, heres how,
log in as root, go to /etc/x11 and look for your xconf config file and open it, go down to monitor section and look for 24 color depth then type in your new resolution, save and your done[/quote]
That's precisely what I have been doing - it makes no difference whatsoever, anyway that resolution is already there.
What has worked is a complete re-install (again), but this time right from the first install screen it has been running in 1024x768 which is what I wanted. How on earth it only ran in 800x600 on three installs before will remain a complete mystery.
Thanks to all who tried to help.
(next question will probably concern Beryl)