Hi,
I used a survey in my course last year and I want to use the same one this year and it will be a different set of students. Do I have to stop the current survey and then how do I activate it again?
Thanks! 

Hi,
yes, it is the best to

• deactivate your survey (export the data before)
• upload the new respondents to the participant table
• activate the survey

how do I activate it again?

??? You press the button 

I doubt that you inserted the "valid from" and "valid to" dates.
 

If you did your participants of the last year have no more access this year.
In this case you only had to upload the new participants.

But remember:
If you activated the survey as "anonymous" there is no "submit date" in the data table.
You will not be able to distinguish between the years.
  
Conclusion:
Best: Deactivate and activate.
In your analysis tool you will have two separated sets where you may add a separation variable to do some statistic tests to compare the groups of last year and this year.
Like t-test for independent groups, tc.

Joffm