On a server it looks like I have SQL 2000 and SQL 2005 installed. I was asked by a software vendor to install SQL 2005 Express on the server. From the looks of it, it was installed and I left things alone. The vendor tells me it's not installed properly and that there is no default instance. Where I see the instances, he says they are not 2005 instances but 2000 instances. I was asked to reinstall SQL 2005. Is this going to be a problem? Is what he saying seem correct? I don't want to cause any problems with existing instances.
When I run the install I get a warning that I am not quite clear on how to deal with it. I am just not strong in SQL.
How can I install SQL 2005 so this vendor is happy?