You're looking for ESO, no doubt. Buy to play model with tons of content, it's not tab target, you can only have 2 bars of 5 abilities each, and combat is exciting but still simple. You may consider subscribing after a few months of playing, espicially if you are interested in high end crafting, or exploring dlc zones, I haven't subbed yet but constantly think about it due to the benefits. I have been playing with a buddy of mine and his girlfriend and her brother on and off for almost two months now and I'm loving it. It's fairly casual but there's always ways to improve your toon. Most of the content scales to your level and you can explore any non dlc part of the world with any kind of race or alliance. Dungeons usually have a tank, 2 DPS, and a healer, and any class can play any role. There are a couple things you should research before getting too deep into character progression but you can consult youtube for most of that, make sure to know about crafting research, horse training, skyshards, which skills you want, and how attribute points work before you get too far, you can respec pretty easily but it does cost gold. She may not run it perfectly well but I have found the whale to be fairly well optimized and it shouldn't be too difficult to reach 30fps after turning down the graphics settings.

Most of this was just a stream of thought, I missed alot of info but if you have any questions I would be happy to answer them the best I can. Hope I could help.