Cannot upload sketch to Arduino Nano I've been using Arduino UNO for quite sometime and brought a new Arduino Nano. When I connected it to my computer, the power usb lit up and the blink sketch started running ( as expected of course).  

Now I opened up the IDE and switched boards. But when I try to upload code to my Nano I get an error- 


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


Clearly the IDE can't see my board. Uploading to my UNO goes fine. The serial port option is greyed out so I can't change it.

I have searched extensively online for a solution and have found none. This must be either a very unique issue or a very simple one.
When using a cheap knockoff Nano, it seems that in the newer versions of the Arduino IDE (at least in 1.8.8), you may need to select "ATmega328P (Old bootloader)" from the Processor options under the Tools menu in order to upload sketches.