Can you tell us what the problem was and how you fixed it.
The time out value is too high drop it down to 50 or 100
SerialPort1.ReadTimeout = 1000Your next steps would be to research a few things to make a better inteface, buttons to open and close the serial port, combo boxes to display baud rates and available com ports.
If you need some help on how to design a dial as a visual percentage indicator then say so and we can give you a start with that.