The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.
One of a set of tools we're offering as a way of saying thank you for being a part of the community.
http://answers.microsoft.com/en-us/windows/forum/windows_vista-windows_update/kb3013455-ms15-010-causes-font-corruption/8640d38d-19bd-46b6-9af0-6213c05107d3
KB3013455 is a security update and uninstalling it may not be a good idea. Microsoft will likely issue a fix.