u s b

[munnaamin]

my dell insperon n5110 has usb port which provide power but does not recognise any usb device

 

[harmster]

Maybe you can check in the BIOS if the USB ports are deactivated.

Check under Advanced -> Miscellaneaus Devices and check all USB functions.
You can also try removing the USB root hubs. In device manager, under USB controller, you will find many USB root hubs, right click on each one of them and click on uninstall, and remove all of them, and restart your computer.

Or, just try to update your bios to the latest version. Set your BIOS to default settings and hopefully it will fix the USB issue.

Good luck