Few options:
- Use a USB headset (or one of
these if you would rather use your existing headphones.) Twilight Sparkle might even sound a bit better.
- Get a
Express Sound card (or
PCMIA card) for your laptop.
- Manually disable your speakers in Control Panel - Sound - Playback devices
- (Maybe) You could replace that board inside your laptop with that plug on it, if it is separate from the motherboard. It really depends on your laptop, and even if it is possible, it is likely a very involved process. Likely, you won't want to do this.