Ok, I somehow managed to delete the thing by activating a hidden Administrator and then take ownership according to this tutorial:
How to Enable / Activate Hidden Administrator Account in Windows? - AskVG
Man, now that was a PITA. I remember having big problem with a released update before that everyone suffered from just because I was so impatient to install it on the same day of release. I guess I'm too stubborn to learn that I should always wait a couple of days before installing any updates from MS.
Anyway, are these installed software that I mentioned earlier really needed for the update to function? (Visual Studio 2010 x86, x64 and Visual Studio Tools 2010 for Office Runtime)
Didn't work on Win 8.1...