XP install problems

I'm trying to install 8.0-beta2-dev3 onto a windows XP pro sp1 box, but
having problems.

During install it gets as far as wanting to connect to instance to activate
the procedural language files, but then fails to connect and reports an
error 'connection refused <0x0000274D/10061> is the server running on host
"127.0.0.1" and accepting TCP/IP connections on port 5432?

If I let the rest of the install run it reports another failure to connect
and 'server closed the connection unexpectedly...', but then a succesful
install

Opening up pgadmin shows the database, but any attemot to connect fails with
'could not receive server response to SSL negotiation packet.  Connection
reset by peer (0x00002746/10054)'

The box is networked on my lan, is not running a firewall, and I've tried
installing from my usual user (with admin privlages) and from administrator
- both with the same results.  I've tried installing using the default user,
and adding a user explicitly myself.  Anti virus software has been disabled.
All options taken are the defaults.

The postgres service appears to be running, and I can shut it down and
restart it fine.  Checking running processes shows that postmaster.exe,
pc_ctl.exe, and three postgres.exe processes running.

The log files, in postgresql/8.0-beta2-dev3/data/pg_log report a great many
errors (incomplete startup packet etc) with the common line 'an operation
was attempted on something that is not a socket'

Perversly, if I try installing it on my server (windows 2000 a/s) then it
all goes in fine, but I'd like a local install as I want to try some Delphi
development against it.  I've tralled through the lists/faqs, but without
any success.  What should I attempt next?

Thanks

Kevin Woolley