I cannot boot my laptop because one of the keys are broken so it keeps on pressing itself, and the laptop will not boot if a key is held down. It just PLAYS an incessant high-pitched tone until you let go of the key, but I can't because it's the keyboard itself.
I need to somehow disable the INTERNAL keyboard so I can boot it.

I'm using an Acer Aspire 5336-2281.No, you have no no easy way to doable it. Open the case and unplug the keyboard. Also, find the stuck key and fix it or remove it.Also to note that some laptops require internal keyboard present to boot, otherwise it hangs at the keyboard error even if a USB keyboard is plugged in, because the USB Keyboard is not active until the system is told to skip this error. Some BIOS's have an option which you can CHANGE the system not to hang on keyboard error, but still you need to be able to make changes without a key being stuck down which will likely interfere and this option is mainly for desktops so that they would boot with no mouse and keyboard attached if used as a server etc where no keyboard has to be attached. If this laptop had a PS2 PORT, you would have instant keyboard access without the internal keyboard CONNECTED, but very few laptops these days have PS2 ports available.