Cubase Elements 7 - novation impulse midi keyboard

Hi. I have very limited experience with using midi keyboards. I was lucky to get kontakt player 5 up and running with a sample library this week.
Managed to record a test piece. However, today I am not able to get any sound from the keyboard - neither in Cubase nor in kontakt. I’ve tried a few times after restarting my computer. I do get sound when I write sheet music in Cubase. I’d be glad to be able to get back to recording. Thanks in advance. Have a nice evening.