Hey ijoin, there are several ways to do this..
a quick way is to use instance variables
presuming that your popup is an object...goto its properties and add an instance variable
make it a Boolean and then give it a name like "Playe_ticked" or something that you recognise
Then you can add an extra action to the Player clicked on "never show it again for me"
The action would go anywhere before the popout action that you should already have for the popup..
and it should trigger the Boolean instance variable that you just made for the Popup object and set the BOOLEAN to true...
then in your other condition that makes the popup initially trigger you should place another "Condition"
that checks if the Boolean has been triggered or not
this way the popup object event will not occur if its been ticked by the player..but should trigger if it hasnt
Hope that made sense..