usb port problem

i plugged my usb cord into my pc and the pc switched off, i turned it on again and plugged a usb device into it but it doesn't detect it. i've tried with more devices but none of them are being detected.

anyone know what i can do to fix this problem?

p.s iv'e tried troubleshooter and restarting the computer various times but it still doesn't detect any devices.

Thanks :)