Ok, so this one is a bit of mess, but I am out of idea.
I was attempting to use a DK2 on a computer which supposedly had already successfully been used to run Unity 4 projects with DK2s. Runtime was indeed already installed, but nothing was showing up on the config utility, nothing was detected.
So I tried to reinstall runtime. But I couldn't, due to a LibOVRRT DLL being in use , and blocking the uninstallation of the old runtime. Of course I have no idea what could be using said DLL, but closed pretty much anything I could. I looked for the dll in system32, found 3 with similar names ( LibOVRRT64_0_6, LibOVRRT64_0_7, LibOVRRT64_0_8 ) and looked up if any of them were in use with tasklist. They weren't. So, not finding much in term of people having the same problem, I deleted the old runtime manually, prayed for CCleaner to put the registry in order, and then attempted a new installation, which after a few seconds, prompted me with :
"One or more applications have LibOVRRT DLL in use. Please close the application(s) to continue the Oculus Runtime installation."
I just have no idea what to do now. Any help would be appreciated.