Windows 7 Can't show removable devices on My Computer

[Peter123]

I accidently somehow disabled usb ports to not recognise removable devices and can't seem to retrieve it. I've tried plugging different usbs into my laptop but the icon does not appear in My Computer. An autoplay pop up the screen for one second asking me what do I want to do with the usb I inserted then disappears. None of the removable devices seem to appear on My Computer. Except for MP3s. Please help fast!