If you simply want a free, lightweight, 64-bit DAW that feels like Cubase 5, consider these options. They are legal, safe, and often more powerful.
Let’s be clear: there is no legitimate "free download" of Cubase 5 from Steinberg anymore. The software is discontinued and unsupported. However, you may still find your original installer if you purchased it years ago.
Cubase 5 has never been released as freeware or abandonware by Steinberg. It is Not Free Software