Hi, i have done a full reinstall of windows, and bought a copy of Windows 10 Pro, and upgraded to that.
However i made sure to test it before i upgraded, and a full reinstall of windows did solve problem.
Sadly nothing else i tried solved this problem, but i hope that some of steps done can help someone in right direction if they are having a similar issue.
For me a full reinstall of windows seems to be what was required, or maybe as Eric stated, if possible to uninstall ALL .NET Framework VS installations and reaquire them using Windows Update.
It is not required to update to Windows 10 like i did, but i decided to upgrade from Windows 8.1 while i was at reinstalling it.
I am however unsure if Free Upgrade to Windows 10 will solve my problem, as that does not reinstall windows, only upgrades it. In my case, my windows seemed broken as i was unable to update using Windows Updater, and therefore i went with a full reinstall.
Best Regards