When you buy some audio software, it comes with a small USB dongle that you install onto your machine. If the dongle is missing, the software won't run. I assume you're getting this when trying to launch cubase. A reboot should work. If not, then maybe your USB protection device is faulty. Contact Steinberg or your reseller for support.
You can get Cubase from Steinbergs website
For Cubase Studio, Artist or the full Cubase program (not LE or AI), insert the USB copy protection key into the computer. Open the eLicenser Control center program that installed with Cubase. Get the license code card that came with the program and click on Enter Activation code. Type the code on the card and press continue. You will need to be online to active. The activation will then be stored on the key, allowing you to run Cubase on any computer you wish, as long as the key is inserted in that computer. For Cubase LE and AI, follow the steps in the Youtube video below under Related Links.
Select the GuitarPort ASIO drivers in the VST Multitrack section of the Device Setup menu.
With Cubase.
YOu forgot the important part: How do you use WHAT in Cubase
You can change the latency settings in the Device menu. Devices>Device setup>Vst Audiobay You might need to change the latency/buffer setting in your soundcards settings also :)
Cubase 5 is no longer sold or produced due to the release of the newer Cubase 6 and Cubase 7. These newer versions of the software retail for $400 each.
A. Isolation of the device
No, a circuit protection device must open the circuit on a fault current or overload.
A device with an overload protection used to control a motor is an Overload Relay.
Cubase is better for the beginner. ProTools is not considered a "home" recording solutions. Try the simpler version of Cubase, Cubase Essentials.
An umbrella