I need help getting a graphics card. I have a Dell E521 and I wanted to get either a 8800 GTX or a 8800 GTS, I'll probably get the cheaper one. But I wanted to make sure that it would fit in my computer. Will I be able to just plug it in and have it work, or is it really complicated to install a graphics card? And also I've been reading about it and all of these sites that review graphics cards say that you should buy two of them, but there is no way that I could afford that, would games still run fast if I just bought one?