To make text and on-screen items clearer in programs that aren't designed for high DPI

If you set the dots per inch (DPI) higher than 144 while you're running Aero (the premium visual experience of Windows), text and other items on the screen might appear blurry in some programs that aren't designed for high–DPI display in this version of Windows. You can avoid this issue by using Windows XP style DPI scaling for these programs.
Some programs display better using Windows XP style DPI scaling.
1. Click to open Display.
2. Click Set custom text size (DPI) in the left pane.
3. Select the Use Windows XP style DPI scaling check box, and then click OK.
   To see the change, close all of your programs and then log off of Windows. This change will take effect the next time you log on.