Well one day I was playing Frets On Fire (Guitar Hero clone) on my desktop computer. My main computer is my laptop, So I wanted to connect my serial keyboard that came with the desktop to my laptop. Now for some weird reason, It looks like I have a serial port that is blocked by some covering on my laptop. It has a S so I think it stands for serial? And one more thing:
My desktop computer is 3 years old, So this is why it uses serial ports for keyboard and mouse.