My arduino is not connecting

Hi I have an arduino uno R3 It's not connecting to my pc. When i connect it via-usb the led on the arduino is red but it don't show up on my pc. Yesterday, it was working well. And my second arduino is connecting well. Do you have an idea why now it's not connecting? thank you

Which operating system you are using??

Check in device manager -> port section-> whether your arduino board detect or not. if detected but highlighted yellow mark means you need upload driver again. If not detected then some other issue. just replace cable

When you connect uno board & upload the program do you get any errors??? if yes post those error in screen shots

it's not detected. And I tried different cables. Do you have have an idea plz?

Post a link to where you bought the board from. Also post a picture of your device manager before and after plugging it in.