Why Does My Sister's 2DS Not Work

I couldn't really think of a way to explain this in the title, but basically, whenever me or my sister tries to use her old Nintendo 2DS, we can use it for a few seconds before it suddenly says it needs to restart. This is what it looks like.

Actually it lasted more like twenty seconds that time. But anyway, we don't know why it suddenly started doing this or if we can even fix it at all, but I have been asking about my 2DS trying to fix the write protection, and I thought I may as well help out my sister while I'm at it.