problem uploading to board error

o/s : windows7

board : arduino uno ( atmega328p-pu )
sparkfun electronics : learn diy ~ kit box

sketch file : examples -> basics -> blink

" can't open device ~ com4 ~ " messsage means, I thought windows7 driver,
so I tried applied FTDI, CH341, ATMEGA328P DRIVER, CDM, but I can't fix up.
SO, I don't know, How to fix it.
What is the cause?

I am trying another. arduino 1.0.6 version

but, another error messag is
" serial port 'com4' is already in use message. Quit any other programs you use. "
(FTDI driver)
hmm.

Try restarting your computer.

I have already tried many times. on / off

Please do this:

  • (In the Arduino IDE) File > Preferences
  • Uncheck the checkbox next to “Show verbose output during: compilation”
  • Check the checkbox next to "Show verbose output during: upload
  • Click “OK”
  • Sketch > Upload
  • After the upload fails, you’ll see a button on the right side of the orange bar “Copy error messages” (or the icon that looks like two pieces of paper at the top right corner of the black console window in the Arduino Web Editor). Click that button.
  • In a forum reply here, click on the reply field.
  • Click the </> button on the forum toolbar. This will add the forum’s code tags markup to your reply.
  • Press “Ctrl + V”. This will paste the upload output between the code tags.
  • Move the cursor outside of the code tags before you add any additional text to your reply.
  This report would have more information with
  "Show verbose output during compilation"
  enabled in File > Preferences.
Arduino: 1.0.6 (Windows 7), Board: "Arduino Uno"
Binary sketch size: 1,082 bytes (of a 32,256 byte maximum)

processing.app.SerialException: Serial port 'COM4' already in use. Try quiting any programs that may be using it.

	at processing.app.Serial.<init>(Serial.java:171)

	at processing.app.Serial.<init>(Serial.java:77)

	at processing.app.debug.Uploader.flushSerialBuffer(Uploader.java:77)

	at processing.app.debug.AvrdudeUploader.uploadViaBootloader(AvrdudeUploader.java:175)

	at processing.app.debug.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:67)

	at processing.app.Sketch.upload(Sketch.java:1666)

	at processing.app.Sketch.exportApplet(Sketch.java:1622)

	at processing.app.Sketch.exportApplet(Sketch.java:1594)

	at processing.app.Editor$DefaultExportHandler.run(Editor.java:2382)

	at java.lang.Thread.run(Thread.java:619)

processing.app.debug.RunnerException: Serial port 'COM4' already in use. Try quiting any programs that may be using it.

	at processing.app.debug.Uploader.flushSerialBuffer(Uploader.java:101)

	at processing.app.debug.AvrdudeUploader.uploadViaBootloader(AvrdudeUploader.java:175)

	at processing.app.debug.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:67)

	at processing.app.Sketch.upload(Sketch.java:1666)

	at processing.app.Sketch.exportApplet(Sketch.java:1622)

	at processing.app.Sketch.exportApplet(Sketch.java:1594)

	at processing.app.Editor$DefaultExportHandler.run(Editor.java:2382)

	at java.lang.Thread.run(Thread.java:619)

There must be some other program on your computer that is opening COM4. COM ports can only be opened by one program at a time.