Installation 8.4 > 9.1

Dear all,

I've got myself into a bit of a mess with my versions. I'm running
Windows 7 on a 64bit machine. When I start PgAdmin I get two servers -
8.4 and 9.1, both running on the same port number. I can double click
and login to either of them fine - although when I do SELECT VERSION()
in either of them, it always says 8.4. So I suspect that although it's
allowing me to double click and login to version 9, it's just kidding
me. I tested this by going into Windows Services and manually
disabling 8.4 server - and then trying to login to 9.1 through
PgAdmin. I got this message:
__________
could not connect to server: connection refused
(0x0000274D/10061) Is the server running on host "localhost" (::1) and
accepting TCP/IP connections on port 5432? could not connect to
server: Connection refused (0x0000274D/10061) Is the server running on
host "localhost" (127.0.0.1) and accepting TCP/IP connections on port
5432?
__________

Could someone guide me as the best way to sort this mess out please?
I've used PgAdmin to do a back-up of my server, so maybe deleting both
installs of PostgreSQL and starting again might be best? Though I'm
worried about losing a few days in trying to do this which I can't
really afford at the moment.

Thanks

James