I cannot connect to a SQL Server 2000 database. I'm trying to create
an ODBC connection, but this isn't working.

I downloaded a Microsoft document on this issue, 328306, I think I've
done everything in that document, but still no results.

Unfortunately, the problem is not any of the obvious fixes.

I disabled the firewall, no luck though. Then, I changed the port from
the default 1433 to 9100, which was available. The computer
is currently listening on that port, I have verified that.

I went into the SQL Server properties, I made sure that TCP/IP used port 9100.

Did all that, can telnet to the port remotely, but still cannot make
an ODBC connection.

This version of SQL Server also has the latest service pack, 3a, so I
don't think that is the issue.

Quite frankly, I'm running out of ideas. The fact that this worked
before, but now doesn't, really puzzles me.

By the way, I went into the event viewer log, and it says that SQL Server started.

Please help if you're able.

Could you go a little further....

What is your set up? ie You have two computers on a home network, or
you are connecting to a sql server at a datafarm...
When you say it used to work, what changed?  Why did it stop working
(ie installed new software, moved machines, etc.).

Not 2 computers on a home network, connecting over TCP/IP from client to server.

No change to software or hardware. We went on vacation, on return, it
stopped working.

Everything else on server can be remotely connected to but SQL Server.

What is the error message you are getting?