I have 2005, 2008 (not R2) and 2012 instances installed on a workstation. I disabled 2005 (turned all the services off) and only need to have 2008 and 2012 instances running.
When adding new aliases or changing the existing aliases for 2008 and 2012, what services do you need to restart.
The alias I setup for 2012 works as expected but the other for 2008 simply brings up the 2012 instance when I make a connection in the 2012 SSMS.