This will show you how to change the DPI (Dots per Inch) size settings to allow text and other items, such as icons, fonts, and windows, to display larger or smaller in Windows 7 and Windows 8.
Reg key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Hardware Profiles\Current\Software\Fonts
LogPixels(dword):<DPI>
100% = 100*0.96 = 96 (decimal) = 60 (HEX)
125% = 125*0.96 = 120 (decimal) = 78 (HEX)
150% = 150*0.96 = 144 (decimal) = 90 (HEX)
Reference
https://technet.microsoft.com/en-us/library/ee681619(v=ws.10).aspx