overwrite 2008 default instance into updated one- best way?

the server has two sql instances
2008R2 instance
2012 instance (named)

the 2008R2 service has been stopped and only the named instance is being used now.

what will be the right procedure to install a default instance (not named) 2012 instance to stand alongside of the named instance?

should i first uninstall the 2008R2? what is the best practise on this?
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Scott PletcherSenior DBACommented:
You must uninstall the current default instance to change to a different default instance.

I'm not sure if SQL will allow you to install a default instance with a named instance already on the server.  I'd have to look that up ... or if you have time, you could just try it :-)

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25112Author Commented:
uninstall and reinstall helped. thanks. (yes, it did not allow default)
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Microsoft SQL Server 2008

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