Alright, after going over the logfiles it turned out to be quite an easy fix.
00000.001 INFO LAUNCHER: Launch command: C:\Program Files\Eagle Dynamics\DCS World\bin\dcs.exe --noreplay --trackfile "C:\Users\SwoXx\AppData\Local\Temp\DCS\LastMission Track.trk" "C:\Users\SwoXx\AppData\Local\Temp\DCS\tempMission .miz"
00000.002 ALERT LAUNCHER: Launching process 'C:\Program Files\Eagle Dynamics\DCS World\bin\dcs.exe' failed with error code 740, command line: --noreplay --trackfile "C:\Users\SwoXx\AppData\Local\Temp\DCS\LastMission Track.trk" "C:\Users\SwoXx\AppData\Local\Temp\DCS\tempMission .miz", current directory: (null)
I just deleted the folder where it was trying to load some mission from, and now it works again.
:doh: