I had this problem where my PC wasn't detecting my Arduino Uno and I found out that the drivers weren't being installed. In the device manager it said that the device was unknown (or something like that). I figured out it the drivers were called CH340, so I did a search online and found a website to get them from and it worked. It's all in Chinese and seems just a tad bit sketchy, but I haven't gotten a virus yet though so seems okay. Here's the link...
PS - Do not hold me responsible if you get a virus or damage any of your soft/hardware. I'm just sharing what worked for me.