We regularly see computers with broken and failed USB ports being brought in for repair. While USB ports used to be a novelty and convenience on computers, increasingly computers require working USB ports for the keyboard and mouse.
Computer manufacturers have been phasing out the use of mini-DIN keyboards and mice and using USB ports instead. USB ports provide higher electrical current output, allowing keyboards and mice to add more features that require power.
Although USB ports are keyed so that they can only be inserted one way, it is possible to force the USB connector in upside down and damage the four pins. Since the +5v power and low voltage data signal pins are adjacent, a broken USB port can also destroy the USB controller chip and circuit on the motherboard. When this happens, all USB ports stop working and cannot be repaired.
For desktops that have mini-DIN keyboard and mouse connectors, they can be repaired using an add-on PCI USB card. It is also possible to install an add-on USB PCMCIA/PC-Card/ExpressCard in a laptop to provide USB ports when the internal ports have failed. For desktops that lack mini-DIN connectors and have failed USB ports, the main circuit board (motherboard) should be replaced.