From EQ website:
We have completely redone the installation and activation process with EQ7. EQ6 does not need to be installed on the computer prior to installing EQ7. You just need to type in your EQ6 license ID and password during the EQ7 setup. If you lose your EQ6 CD or run out of EQ6 activations, you will still be able to install the EQ7 Upgrade. Just don't lose your EQ6 License ID and Password.
And don't worry. You’ll never run out of EQ7 activations! Activation and deactivation is as easy as two clicks of the mouse. Install on as many computers as you like and quickly transfer activations from computer to computer. This new policy gives you complete freedom to manage your own activations