To solve this problem you have to select my computer. Now press right button of your mouse & select properties. Click on hardware tab. Now click on device manager button. You will get device manager window. Click on universal serial bus controllers. Now you will get a list of usb ports. Select one of them & press right button of your mouse. Now select uninstall. You will get confirm device removal windows & you have to click on ok. Now do same thing again & again to uninstall all usb ports. When universal serial bus controllers will have no usb port to delete close device manager. Now restart your pc & insert your pen drive. Windows will automatically install usb ports & you will be able to use your pen drive.