SQL Server Express 2008 Install Side-by-side w/ SQL 2005 Express Fails

When I try to install a new instance of SQL Server 2008 Express on a development machine with SQL 2005 Express already up and running, the install validation fails because the “SQL 2005 Express tools” are installed and I’m told to remove them.

What exactly does that mean?

After reading this article:

http://www.asql.biz/Articoli/SQLX08/Art1_5.aspx

I uninstalled the 2005 version of the SQL Management Studio but received the same error from the 2008 installer during my follow-up attempt.

Updates

1) Uninstalled the SQL 2005 Management Studio only. Received the same error from the 2008 install.

2) Removed all SQL 2005 common components. Received the same error from the 2008 install.

3) Installed the shared components from the SQL 2008 installation program. Received the same error from the 2008 install when trying to install the new SQL 2008 instance.

4) Uninstalled SQL 2008 components, rebooted, re-installed SQL 2005 Management Studio from installation media, rebooted, un-installed SQL 2005 Workstation Components from Control Panel, re-booted.

Installation of SQL 2008 is now proceeding as it should.

Seems likely that if I’d re-booted after update 2 above things would have gone more smoothly. 🙁