arduino nano problem

Using Arduino Installation & Troubleshooting
#1

Hello

I bought a arduino nano replica recently but now when i try to upload the program it says:

avrdude: ser_open(): can't open device "\.\COM3": The system can not find the file specified

anybody can help with this?

thanks in advance

#2

Try to reconnect the board. or, exit all the programs, start arduino only.

#3