could be latency especially when an audio recording is running.
It depends on your soundcard driver or monitor settings(somewhere in the upper left corner)
see to it that the sample rate used in cubase matches the rate of the soundcard.
check in and output routings...............................
With the machine in front of me I would find the prob. within 15 minutes.
But I live in Belgium!
Don't get nervous you'll solve the prob.
Experience improves your skill.
kind regards
pax