Open up "Personalize" by right-clicking on the desktop and then click on "Display" which can be found on the lower left hand side of the window. It almost sounds like the default DPI settings are off, but you should be able to change it there.
To answer Anderson's question below, you need to know some background info. There are three levels of DPI awareness starting with Windows 8.1: Not DPI Aware/Unaware, System Aware, and Per-Monitor Aware. The applications themselves determine their level of DPI awareness. Applications that are DPI Unaware are scaled up through a feature call DPI virtualization. It is this DPI virtualization feature that scales the application and introduces blurriness when doing so. Unfortunately, at this time, there is a non-trivial number of programs that do not support DPI-scaling. Even Microsoft's own Office suite doesn't yet support Per-Monitor DPI Awareness (2017-8-24).
By setting the DPI to 100%, there is no scaling, hence no blurriness.
To see what level of DPI awareness applications support, you can use the wonderful Process Explorer tool. Using Process Explorer, Select the View file option menu, and in the drop down menu, select Select Columns…. In the window that opens, select DPI Awareness. Process Explorer will now list all the running applications with the DPI Awareness column which will list one of the three aforementioned options.