If I completely finish this spring semester, then do not pay/register for next semester/year(Fall 2017), am i get automatically withdrawn from college? Or should I turn in the withdrawal form(right after the new semester starts?) in order to completely withdraw?
I would ask at the registrar’s office.
Talk to your adviser about this ASAP. Make sure to do it right.
It is important to follow the rules of your school to the letter. Doing so might insure you have the option (even if yo don’t want to at this point) to return at a future date. Nice to have options.
Speaking from personal experience, please go talk to an advisor about this, or at least someone at your school. I did exactly what you’re suggesting and ended up screwing myself over completely in terms of loans, financial aid, and some money I owed the school. It turned into a huge mess once I ended up transferring somewhere else that could’ve been completely avoided.
Also, as someone else already stated, you also might want to make sure you have the option to return. Are you leaving this school completely, or taking a semester off? Usually schools have a way for you to work out taking a gap year and returning.