Upgrade/Reinstall Question

Hi,

I've been running Parallels 5 for quite some time on my laptop and wanted to upgrade to Parallels 6.0. I by accident bought a new copy of Parallels 6(instead of the upgrade version). What is now the recommended way of working?

1) Deinstall Parallels 5 and reinstall version 6
2) Just insert de Parallels 6 DVD and do some kind of upgrade? What about the licensing key then? Because I know basically have to different licenses.

Or is there a third and better solution for doing the installation?

Thanks,

Jurgen