In other threads I have described endless problems.
So now I will try a new approach.
I will attempt to describe what I did and what happened.
Then maybe my mistakes will be obvious to you.

19:00 Booted to XP and deleted existing Linux partitions,
leaving 13GB of unallocated space at end of HDD.

19:04 Booted XP CD to Recovery Console and used fixmbr and fixboot.

19:08 Booted Sarge DVD and used hostname "debian" and no domain name -
because I didn't know what that was for.

19:12 "Installing the Debian base system"

19:15 GRUB to MBR; removed DVD; system rebooting.

19:17 "Welcome"; root pw; CDROM for apt; DVD back in.

19:19 "Scanning Disc for index files"

19:21 Selected "desktop environment" by pressing the space bar.
I hadn't realised before that you had to press the space bar - to get an
asterisk into the checkbox. The checkbox was highlighted - so I thought
you just had to press enter.

19:44 (NOW) Loads of white writing is flashing by on a black background.
This has been going on for ages. Last time I aborted at this stage -
because the messages made me think it was fetching lots of stuff from
the Internet - but maybe it wasn't? Haven't a clue what's happening!
I will wait a while and see what happens next.

19:47 (ANOTHER NOW) (This is real stream-of-consciousness writing!)
Something has happened.
"Configuring xserver-xfree86"
Well ... there is a driver called ati ... so I'll go for that.
The card is an ATI Radeon 7000.

19:53 Do I want the mouse and monitor autodetected?
Yep - might as well. Scrubbed the mouse around enthusiastically, in an
effort to co-operate.

19:56 Loads more scrolling writing on screen.
Says it's selecting things that were previously deselected.
That sounds indecisive to me!
Lets categorise that as a mystery - and relax.

20:06 "Configuring Exim v4 (exim4-config)"
I don't understand the questions here.
Mine is just a home computer - connected to an ISP via a router.
None of the options seem to apply.
I will say "no configuration at this time".

20:10 More questions about mail. Don't understand at all.
Muddled through.

20:14 Graphical login screen appeared - and I logged in as a normal
user.
WOW - Has this actually worked at last?

I'm off to play with it now - but - is there a checklist of things I
should do next?

If it was XP I would be installing ZoneAlarm and AVG antivirus etc.
and doing loads of configuring.

What's the equivalent for Debian?
--
Chris