Serial Python and Arduino

[delfar]

Hello,

I am trying to write a base program that will connect to an Arduino, Via Serial, and will send and receive data. 

For some reason though, I can't seem to get Python to connect with the Arduino Uno. 

Here is the code I have, and the error that I get. 

If anyone knows a possible solution, any help would be great!

import serial

connected = False

ser = serial.Serial("COM3", 19200)

while not connected:
    serin = ser.read()
    connected = True

myStr = "1"
asBytes = str.encode(myStr)

ser.write(asBytes)

while ser.read() =='1':
    ser.read()

ser.close

Error:
runfile('C:/Users/Christopher Martone/Desktop/pythonArduino.py', wdir='C:/Users/Christopher Martone/Desktop')
Traceback (most recent call last):

  File "<ipython-input-3-f2cfc99aed65>", line 1, in <module>
    runfile('C:/Users/Christopher Martone/Desktop/pythonArduino.py', wdir='C:/Users/Christopher Martone/Desktop')

  File "D:\Anaconda\lib\site-packages\spyder\utils\site\sitecustomize.py", line 866, in runfile
    execfile(filename, namespace)

  File "D:\Anaconda\lib\site-packages\spyder\utils\site\sitecustomize.py", line 102, in execfile
    exec(compile(f.read(), filename, 'exec'), namespace)

  File "C:/Users/Christopher Martone/Desktop/pythonArduino.py", line 12, in <module>
    ser = serial.Serial("COM3", 19200)

  File "D:\Anaconda\lib\site-packages\pyserial-3.3-py3.6.egg\serial\serialwin32.py", line 31, in __init__
    super(Serial, self).__init__(*args, **kwargs)

  File "D:\Anaconda\lib\site-packages\pyserial-3.3-py3.6.egg\serial\serialutil.py", line 240, in __init__
    self.open()

  File "D:\Anaconda\lib\site-packages\pyserial-3.3-py3.6.egg\serial\serialwin32.py", line 62, in open
    raise SerialException("could not open port {!r}: {!r}".format(self.portstr, ctypes.WinError()))

SerialException: could not open port 'COM3': PermissionError(13, 'Access is denied.', None, 5)