Hm... that's strange. Well, there's one thing you can do, but it'll delete all of your settings:
Go to
C:\Users\$User\AppData\Roaming\
and delete the .kde folder. Then open up Krita.
What I suspect happened, is that you chose a different colour profile in either file->new file or settings->configure Krita. (both are supossed to be sRGB-elle-srgbtrc.icc)
Krita has some very complex colour management in place because that is important for industry proffesionals, but it can mean everything will look odd if you acidentally toggled something
You can try to change it back manually, or reset Krita by deleting the .kde folder. Good luck!