There are two versions of Cubase 7:
Activation codes for older versions of Cubase are one-time use. Once they are tied to a MySteinberg account and a USB-eLicenser, they cannot be used again. How to Legitimately Activate Cubase 7 license activation code for cubase 7 full
Even if you find a "working" crack (which usually involves replacing the cubase7.exe file with a pirated one): There are two versions of Cubase 7: Activation