Well I should also mention that I'm absolutely clueless when it comes to computers and im just looking to run dark souls maybe wow and a couple other games I don't need anything out of this world just something that will work and I have this all in one to my disposal so I wanted to start there because... in terms of money....we have no money@Prztkoa how are you recommending a processor without knowing the specs to the prebuilt? The specifications list shows that the AIO comes in multiple SKU's meaning multiple different configurations. To add, I don't think throwing money at a near two decade old system will bring about any positive returns on investments.
Regardless, might want to parse the specs to your AIO or an SKU to it. As for the build, how much can you spend if we/you were to look at a new build to get your feet wet?