code cannot upload

I am using IDE 1.8.1 and when I tried uploading a code it said it could not locate the board, when I checked the port in tools menu it was greyed out. I uploaded a code on this same board yesterday on the same board,yet it does not work today. why??? and what is the solution.

thank you in advance

Are you using the same computer as when you successfully uploaded to the Arduino?

Are you using the same USB cable?

Try restarting the computer.

I am using same computer and usb cable, I tried restarting but I still got the same problem

Try disconnecting everything from the Arduino except for the USB cable.

still not working

ujwaljoshi:
still not working

What's still not working is your complete lack of details.

Unplug EVERYTHING Arduino-related from the PC. Start the IDE. See what, if anything, is available under the Tools + Port menu.

Shut down the IDE. Plug the Arduino in. Start the IDE. See what, if anything, is available under the Tools + Port menu.

If there is nothing under the Tools + Port menu the first time, but there is the second time, then the Arduino is connected to the new entry.

If there is nothing under the Tools + Port menu either time, you've hosed the Arduino. Get a new one and don't do THAT again (whatever THAT was).