Upload not working, stk500_getsync() with different hex codes

Hello, I got a strange error while using the Arduino Uno with Windows 7. After working with it for months perfectly, my computer suddenly fails to upload the sketch to the board with these errors:

Arduino: 1.6.7 (Windows 7), Board: "Arduino/Genuino Uno"

Sketch uses 450 bytes (1%) of program storage space. Maximum is 32,256 bytes. Global variables use 9 bytes (0%) of dynamic memory, leaving 2,039 bytes for local variables. Maximum is 2,048 bytes. avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x64 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x64 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x64 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x64 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x64 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x64 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x64 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x64 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x64 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x64 Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

This report would have more information with "Show verbose output during compilation" enabled in File > Preferences.

I tried to:

  1. Replug the Arduino
  2. Reinstall the Toolkit
  3. Use another computer
  4. Use another port

After that, I thought that it may be permanently damaged and bought another one. That one worked for a few uploads, but then it got exactly the same errors. Sometimes it's another hex code behind it, but the result stays the same. The "L"-LED next to pin 13 is not flashing but stays on. What shall I do?

Yours sincerely,

DLCom

What arduino model? Clone? Make sure port and board are correct in the IDE. Different boards even if they are the same model will have different COM ports. Other than that, try reinstalling the drivers, they are known to go crazy.

Make sure they are listed in the device manager.