So, like is changing the video card from a pc easy and do I need to have some sort of programming knowledge? I don't really want to set off on this project not knowing anything

Also, what would be THE brandname to be looking at? I'm kinda looking for something that can process all the games on todays market. But, I can settle for a bit less, depending on the price

Lastly, is this a quest that is worth taking or would it be easier for me to just build a pc myself with all the goodies I want?