I shouldnt think that dropping it would have removed them from the device manager.
A common reason for non functioning USB ports is that they have been disabled in the bios.
Do you know how to get into the bios ?
Laptops sometimes have a different sequence of keys to press than pcs do.
If you dont know howto get into the bios try DEL, F1 , F2, F10 maybe alone or with the Fn key at that same time.
Once in the bios look for onboard peripherals and then look for the USB host controller and make sure that its enabled