I made the mistake of installing Windows 8.1 with the hope that it would fix some of the things I hate about Win8. Foolish on my part.
Just about everything looked like shit after installation. Things were sized wrong, text was blurry etc.
After mucking around for a few hours I finally found a fix. Go to Control Panel->Appearance and Personalization->Display and select “Let me choose one scaling level for all my displays”.
Then, on the next screen, select Smaller – 100%
One more reboot and things (at least for me) looked back to normal.