For fellow Arduinoeans, have trouble with Serial Port with Windows 8.1, follow

For Windows 8.1 users, having Port Serial problem,

Arduino Mega 2560 driver is yet compatible with windows 8.1, But until then,

follow this, helped with this problem 100% for me..:

Credit to: beachedwhale

This is BS. When you download the IDE, you get the driver with it. You may need to do the first part, but select the driver from your download file. I just got a Windows 8.1 computer and it installed all by itself.