Windows 7 - Photo Viewer was really slow

Windows 7 Photo Viewer was acting really slow for loading images, this fixed it:

1. Go to Color management (Desktop -> Screen Resolution -> Advanced Settings -> Color Management -> Color Management -> Advanced (tab) -> Change System Defaults)
2. Remove all profiles from all screens, and add single profile per display. (I chose sRGB virtual device mode profile.)
3. Check the colors in Photo Viewer if the colors are fine then you chose good profile.

That did the trick.