Audio Sync

I am relatively new to Cubase and I just upgraded to Cubase 7.5. I am recorded parts,drums,keys,in VST instruments. When I record the bass line in audio,it is not in sync with the rest of the tracks.I tried recording 10 times or more,and I’m sure, it’s not my timing.I as well quantized and still not in sync.Does anyone have any suggestions on what the problem might be.Thank you in advance for you response.

How do I