So I have a pretty dingy PC. Specs are below.

It's a gateway sx2850 running windows 7 Processor: Intel core i3 cpu 540 @3.07ghz 8 GB Ram 64 bit operating system

My current screen resolution is 1366x768.

Not impressive by the slightest means. I don't need anything to beefy. I play an older game (Nascar Racing 2003 Season) this pc can play it fairly well, but over the past 20 years there have been so many mods and other things released and the pc needs a bit of an upgrade

So my question is, rather than getting a new case, and everything and having to completely build a new pc (I can't do it atm) is there anything I can buy to just give my current pc an upgrade? I didn't know if there were any upgrades that this pc may have had back in the day? I figured if I can find something that is compatible, I won't have any problems with the power slot or anything. (I also don't know much about pcs, so this may all sound dumb 🤣) I know I want to add 8gb ram. But idk what else to do...

The main reason for asking this, is because while the game is very playable, I can't record ny game play without it getting all choppy and slow.

EDIT: I was looking at an i7-870 processor. It's only $10 free shipping.