So just spend a couple hours with Microsoft support techs;
The first 2 didn't manage to solve anything and just repeated what I've attempted previously. The last tech I spoke to, spend about 2 hours trying to fix the problem.
He started services.msc and stopped/(re)started many diffirent services I honestly can't remember.
He changed the file "SoftwareDistribution" to .old and then ran a windowsupdate.bat file with various commands. Next he attempted to reinstall KB2919355, KB2961851 and KB2962123 seperately 1 by 1. After about 3 restarts he finally managed to fix 2 out of the 3. But the dreaded KB2919355 still remains.
Finally he created a new Admin account, because it might've been corrupted user files. Didn't help.
I'll be receiving Tech2 help in a couple hours and hope (s)he can solve the problem.