My issue with fuzzy fonts was entirely solved by disabling DPI Scaling in Windows 8.1. This feature seems to have been around since Vista but I had never used it previously.
In your Control Panel\Appearance and Personalization\Display
- Check the box "Let me choose one scaling level for all my displays"
- Select the radio button for "Smaller 100%"
Setting scaling to 100% means "don't scale" and hence no fuzziness.
Hope this helps.