Safely changing from Mcafee to Norton. Please advise!

Hello there all.

 

I've been running the 90day free trial of Mcafee that came with my Vaio, it runs out in 4days.  Over Christmas I purchased Norton. 

 

Mcafee has a few trojans in quarantine.  How do I safely change to Norton ?  Do I need to download software to remove Mcafee or will this happen automatically at the end of the trial ?  Should I make sure Mcafee is removed first before installing Norton ? Should I disconnect from the internet whilst doing this ?

 

Any further advice any of you guys have would be very much welcomed.

 

Thanks in advance.