Powersupply from 300W to 500W (If i can find a powersupply, That i have, it might work, But is a bit outdated "only has IDE hard drive power connectors, So, I might just use both power supplys, But if i do, I can get a cheaper powersupply...) (http://www.memoryexpress.com/Products/MX35072)
(OPTIONAL: Fan controller, aftermarket CPU cooler)
It depends on the resolution. This is pretty old, but I mean it looks like you are running simple games at least. TF2 is the only one I would think would not run. Then again, it has low graphics settings.
.... Hmm.. Okay, I guess i should not upgrade this? how come? how would this be slow to a computer with similar upgrades? but, I guess, If i can, I will upgrade this... I will see if i can get the new one, but if i dont get it upgraded after the new year, I will just end up building my own... Thanks for the help!