Pentium E6600 Rig Upgrade Ideas

[CluelessAboutTech]

Received an old PC, specs are:

Pentium E6600
Asus G41 Motherboard
2GB of Generic DDR3 RAM
Nvidia 8400GS
Aaaaaand a 450w PSU

Now, I play LoL and TF2 on a laptop and though the desktop runs them way better, it still can't manage to max them out and get high and stable framerates. I figured upgrading would solve this but I don't have much so I went here to ask for suggestions on which parts to upgrade first; the GPU, RAM, or the CPU (to a used Q6600 maybe).

So which do you think I should get first?

 

[ko888]

What's the brand and model of the generic 450W PSU? The information is needed to determine what type of upgrade is possible or worthwhile.

Is this old PC a pre-built consumer system from a brand like Acer, Dell, Gateway, HP, etc.?

 

[CluelessAboutTech]

Checked it. It's a Huntkey Green Power EN450.

By pre-built, do you mean like it was bought from a retailer? If that's the case then no. I believe it was manually built in 2010.