Installation problem in SQL server 2005
Sql Server 2005 will install just fine on a single user system. A better question is why you would want to. Most of the time when I've seen people want to do this, they're using it as a simple data store for a desktop application they are building. If that's what you're doing, you should probably choose an in-process database like Sqlite, Sql Server Compact Edition, or even MS Access instead. Of course there are exceptions, but really if this is part of an app that must coexist with other apps on a machine that will serve as some user's primary desktop, you should really avoid trying to push a whole server at them.