It is all in the name.
With a Non Imm O visa you only get 90 days of stay inside the Kingdom and have to leave to obain a new 90 day period of the visa is multiple entry OR apply for a new visa.
BUT if you got this visa, entered Thailand and visited the Immigration Office to get a new big stamp with the text:
"Extension of Stay permitted up to xx/xx/xx" which is valid for 1 year, you have to report that you are 90 days inside the Kingdom.
Please look in your passport and tell us which one you have OR just show us a picture without any personal details to help you out correctly.
IF it is the big stamp Extension of Stay, you can use this on line system
*******************************************