Nano Port Selection Greyed Out

I am using an Arduino purchased Nano using the off line Arduino IDE version 1.8.12. The port selection function under Tools menu of the IDE is greyed out. The PC does not detect the Nano, there is no ding dong when plugging the Nano into the PC USB socket. The load LED is flashing. The USB device on the Nano is an FTDI device with markings 1917-C, F53773G1 and F1232R1. Since there was no communication, PC to Nano, I installed the Port (COM and LPT) manually as a Legacy device and find there are four drivers within the Arduino drivers folder. Which should I use? Is there anything else I should check? I understand I need to use the old bootloader when I get to uploading a sketch.

Inside the installation folder for the IDE there is one called DRIVERS.
In there is a ZIP file that you can just unzip.
When unzipped the Arduino driver for older NANO's is in there and you can simply point the driver selection using HAVE DISK to that location and use that driver.

Yes you probably will have to use OLD BOOTLOADER.
Some people have also used UNO as a board selection for the NANO but beware that it will list in future as a UNO and not a NANO.

Thanks for your reply!

Following your suggestion, I opened up the Drivers folder within the IDE and found seven sub folders including FTDI USB Drivers. Since my Nano has an FTDI device I selected this subfolder and found three further sub folders and six files. I tried loading two of the six files, ftdibus.inf and ftdiport.inf, via HAVE DISC, each time it asked which model but there was no choice, the installation stalled here. Which files are you referring to when you refer to files for older Nanos? What is the file name extension for a driver file? I briefly tried Uno as a board selection but still no port. This PC and the USB cable have been used successfully with a Nano before.

Just to make sure you are not one of those unfortunate to suffer USB 3.x or win 10 issues.

If you have USB 2.0 ports make sure your board is plugged into one of those and uses a USB 2.0 cable not a USB 3.x cable.

If you have another computer it is often worth trying that too to ensure it is not just a local problem.

If you are on windows 8 or 10 make sure you turned off driver signing from an admin point of view not just a user.

FTDI drivers have not been used on most boards for quite a while due to FTDIGATE so you probably have a much older board there. May be worth you reading up on FTDIGATE to make sure you are not affected by it in any way although it was supposed to be fixed a long time ago by FTDI and Microsoft.

Additionally you should be able to use any of the FTDI drivers you have listed in HAVE DISK or even all of them as the IDE will normally pick the best or most current one.