How can I identify which hardware component is causing my computer issues?

Hey everyone! I'm experiencing some unusual hardware problems with my PC, and I'm hoping to get some advice on how to figure out what's wrong. Here's a summary of what I've noticed:

- I started experiencing random lags while playing a game called BallxPit, especially when there are a lot of particles on screen.
- The lags continued even outside the game and didn't go away after I restarted my computer.
- I noticed that every program was slow to load, my keyboard wasn't registering all key presses, and my mouse was lagging as well. Even the BIOS looked visually bugged.
- I tried reinstalling Windows and flashing the BIOS, but the lags were still there.
- After reseating the RAM, the lags disappeared.
- However, the lags came back when I played BallxPit again.
- I took out one of the RAM sticks, and the lags went away, so I played BallxPit for two hours without any issues.
- I swapped the RAM sticks around, and the issue still didn't appear.
- But then, after a week, the lags returned when I went back to playing BallxPit.
- Reseating the RAM again fixed it temporarily, but no matter how I swapped the RAM sticks, the lags would come back after playing.
- I started to think this could be a specific issue with the game or the RAM.
- Recently, I had the same problem while playing a different game (Magicraft), which used to run perfectly fine for months. Just like before, reseating the RAM fixed the lag temporarily.

So, it seems to be a hardware issue, doesn't it? How can I pinpoint which component might need replacing?