Okay! I hope this is going to be the last time I write to this thread. I have fixed the problem myself. Here is what I did:
- Log into Steam.
- Click Play PSO2, PSO2 Launcher appears.
- Click on "Environment Settings".
- Click "Initialize" (I think this did a master reset)
- Save settings > Back
- Start Game
After testing for 2 hours, and relaunched the game several times, the computer fans no longer roar at full speed.