Can I (without problems) install Microsoft SQL Express on a server that is already running Domino? If not, I could set up a virtual server, but then I would have to buy an extra Windows server license
And since this SQL thing is only going to have a few users, I was hoping that it could/would run on one of my Domino servers.
It depends on how many users are on Domino. SQL Server (any edition) is a resource hog. We ran a SQL Express on the same server with our Domino fax solution, but neither was used a lot.