If you try to install the ConfigMgr 2012 console on a workstation with an existent ConfigMgr 2007 console you will have the following error message:
And even if you click on ok then next you will not be available to see any option then:
Well, in this case you have two choices:
1. Uninstall the ConfigMgr 2007 console then install the 2012 one.
2. Otherwise, if you want to keep both consoles you have to go to the ConfigMgr 2012 media under
\SMSSETUP\BIN\I386 and run consolesetup.exe or AdminConsole.msi
Don’t forget to enter the FQDN of the ConfigMgr 2012 box.
And you will be able to use the two console from your machine.