What version of Premiere Elements are you using, and what computer operating system is involved?
The is no Loop Playback Button in Premiere Elements that I have found in any recent versions. I suspect that you are using some version of Premiere Pro.
Somehow your thread got posted in the Adobe Premiere Elements Forum. If you are using Premiere Pro, please post your thread in the Adobe Premiere Pro Forum to take advantage of the specialized expertise there.
Please look at the first link that I posted to determine if there is anything in it to help you.