I had a problem yesterday that I ended up fixing on my own... decided to post and share my solution in case anyone else can benefit from it (problem stemmed from a botched uninstall.... power outage).
My rift sensor was being reported as "Not detected" within the Oculus App. Device manager was reporting that it was unable to find the driver. Uninstalling and reinstalling the Oculus Software had no effect. I found a folder located in C:\Users\<username>\AppData\Local\Temp\Oculus\ that contained "OculusRiftSensorDriver.msi", but running the installer had no effect on my problem. Here's what worked:
Unpacked the .MSI contents using 7zip and renamed the files as follows:
U ARE GENIOUS!!!! I got DK2 as a gift and have been struggling for 40 straight hours without sleep my wife went crazy! I GOT THE BLUE LIGHT AND POSITIONAL TRACKING SENSOR IS WORKING! Thousands of people with the same problem, and this was the solution! Bravooo!!
I have been going back and forth with support since Sunday because my second sensor wasn't working, it kept getting "Error code 10, cannot start device" when I tried to use the same driver as the first sensor, but otherwise it kept just saying driver not found, I can't wait to try this when I get home! It was working just fine (received it Friday the 25th) until Sunday. I tried all the things you mentioned. The PC I am using for it was running Windows 7 SP1, i5, 8gb, GTX 1050 Ti. It just all of a sudden stopped detecting it. I hope this fixes it!