As far I know, long gaps are not a big deal if you are going for grad studies and you have valid work experience. For under grad, chances are slim to none. Yet, do your own research and hopefully other members would comment on this too.
I agree with Scylla. I had complicated case too with previous visa rejection and application withdrawal. I explained in detail and provided supporting documents as evidence. And I obtained my Canadian study permit without any issues.
Do not lie in your application regarding previous visa...