I have my PS4 set up in my living room and just bought my friend's PS3 for my kids room so she can watch PS Vue. I tried changing the PSN email on the PS3 but it won't let me use my PSN email. Can I use my PSN account on multiple devices? If so, how do I do that? My friend didn't clear anything off the system so all her stuff is still on there, so I don't know if that could be causing the problem.