avrdude: ser_open(): can't open device "\\.\COM8": Access is denied.

Hello everybody. I've got a problem I can not solve. I have a Arduino Uno with the installed drivers. When sending some type of code. For example blink, an error appears.

I have another Arduino Uno and everything is fine with that.

If anyone can help me grateful.

Error:

avrdude: ser_open (): Can not open device "\ \ COM8.": Access is denied.

Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions. avrdude: stk500_recv (): programmer is not responding avrdude: stk500_getsync () attempt 1 of 10: not in sync: resp = 0x25 avrdude: stk500_recv (): programmer is not responding avrdude: stk500_getsync () attempt 2 of 10: not in sync: resp = 0x25 avrdude: stk500_recv (): programmer is not responding avrdude: stk500_getsync () attempt 3 of 10: not in sync: resp = 0x25 avrdude: stk500_recv (): programmer is not responding avrdude: stk500_getsync () attempt 4 of 10: not in sync: resp = 0x25 avrdude: stk500_recv (): programmer is not responding avrdude: stk500_getsync () attempt 5 of 10: not in sync: resp = 0x25 avrdude: stk500_recv (): programmer is not responding avrdude: stk500_getsync () attempt 6 of 10: not in sync: resp = 0x25 avrdude: stk500_recv (): programmer is not responding Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions. avrdude: stk500_getsync () attempt 7 of 10: not in sync: resp = 0x25 avrdude: stk500_recv (): programmer is not responding avrdude: stk500_getsync () attempt 8 of 10: not in sync: resp = 0x25 avrdude: stk500_recv (): programmer is not responding avrdude: stk500_getsync () attempt 9 of 10: not in sync: resp = 0x25 avrdude: stk500_recv (): programmer is not responding avrdude: stk500_getsync () attempt 10 of 10: not in sync: resp = 0x25

Try a loop-back test on the defective board and let me know the outcome. The instructions for the test can be found at the top of this subforum.