Maybe you have installed a lot of new Fonts and maybe made some changes as a result of which some of your software are not working thing broke! In such a scenario, it might be a good idea to restore the fonts to their default settings in Windows 10/8/7.
Restore default font settings in Windows 10
To restore default fonts in Windows 10, Windows 8 or Windows 7, open Control Panel > Appearance and Personalization > Fonts > Font settings.
Here click Restore default font settings.
If you need to repair the font registry you can give FontReg a try. This utility can be used to ensure the consistency of the Windows font registry. It does this by registering fonts that are not properly registered and removing leftover stale registrations for fonts that are no longer present on the system.
See this post if you are facing a Blurry Fonts problem in Windows and this one if Web fonts appear blurry in Internet Explorer.
TIP: Windows 10 lets you block untrusted fonts to keep your Network safe.