can't open COM3: [...] cannot access the file because it is being used.

on windows xp , using arduino 1.6.0, trying upload arduino uno, i'm getting error: 

code: [select]

avrdude: ser_open(): can't open device "\\.\com3": process cannot access file because being used process.

i have board set arduino uno, port com3 (the one) , programmer arduino isp. infact, no matter programmer choose, keep getting error.

i'm pretty sure programmed same board few years ago, don't remember how, or if using same version or (i got 1.5.8).

complete message:

code: [select]

         using port                    : com3
         using programmer              : arduino
         overriding baud rate          : 115200
avrdude: ser_open(): can't open device "\\.\com3": process cannot access file because being used process.



avrdude done.  thank you.

problem uploading board.  see http://www.arduino.cc/en/guide/troubleshooting#upload suggestions.

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