Issues with sound disappearing whenever I activate Cubase

So I recently bought a ZOOM B3 Bass multi-FX unit that came with a Cubase 7 LE. I installed the drivers, selected all the right choices and done pretty much all that ZOOM asked me to do In order to record and use the ZOOM as my soundcard.

And I can use it as a soundcard, I browse the internet, listen to videos on Youtube, listen to my music. But, whenever I activate Cubase, I cant hear anything but my bass guitar. All youtube videos and music files refuse to work and I simply cant hear anything but my bass.

What have I done wrong and is there a way to fix it?

OK, so now I can hear stuff from youtube when ever Cubase is active. However I still cant hear any MIDI tracks I uploaded into Cubase through the ZOOM. I can only hear them if I activate my laptop’s speakers.

If you go to Devices, Device Setup, VST Audio System, you can check the option to “Release ASIO Driver in Background”. This will allow other programs to have access to the audio interface.

This did help with background stuff but it still doesnt explain why I cant hear any of the MIDI tracks that I uploaded to my current project.

Do I have to reroute them somehow?

In Devices, Device Setup, VST Audio System, what is your ASIO driver? If you import an audio file into the project in Cubase, do you hear playback from there? Do you see metering on Stereo Out?

What virtual instrument are you triggering with the MIDI track?