Toon Boom Stopped working / Can't pre visualize imported images or video

Hello guys!

I’m very new with this program, actually I need it because I’m working on a short film so I need to fix this very quick :frowning:
I’m using Toon Boom Harmony 12.1 on my computer but it frequently stops working. Besides, every time I import an image/video, I can’t pre visualize it. It always shows the entire picture/video in black (I’ve attached a screenshot) And when I try to play the video (I’m using it as a layout) Toon Boom stops working again (even when I click a layer to delete it, stops working). When I’m drawing, the brush draws slow. I’ve worked with 3D animation programs before on this laptop and it had no problems.

I’m using a Dell laptop 64 bits, Win 7 and the minimum requirements.
I’ve tried deactivating Aero themes too and closing every program but Toon Boom and still nothing.

Thank you!