How can I start an EC2 instance? thanks!

I am a newly registered user, who can get the host for free When I execute: Start Amazon EC2 instance, I will be prompted: Your requested instance type (t2.micro Windows) is not supported in your requested Availability Zone (ap-south-1c). Please retry your request by not specifying an Availability Zone or choosing ap-south-1a, ap-south-1b.

ap-south-1c is default，How can I start an EC2 instance? or How to reset my account？ Because it seems that I can start for the first time, and then not work when stop and start again.