Please describe your project that caused it to fail. A wiring diagram (photo of hand-drawn is OK) including all power connections will be useful.
With a genuine Arduino Uno, you can run the loopback test and report the results here. Run without anything connected (as mentioned above) except for what is in the instructions.
If device manager does not show the Comms and LPT section at all, I would be very worried. To my knowledge the section will always be there (but I might be mistaken). If the board does not show in device manager, it will also not show in the IDE 