Recently I have bought a new machine that came with Windows 8.1 pre installed. To make the story short the texts and some icons were super blurry an fuzzy, edgy. I have spent some hours on the net and found a clue that says new Win8.1 has sometimes the text size increased by default. So what you'll need to do to restore 100% size is:
1. Go to the Control Panel and open Display
2. Then see if you have an automatic selected, if so then have it overridden
3. The default is always 100% so make sure it is selected that way, hit Apply then log out and log in