I had a error over the last two days with a system that would not allow me to install dot.net 4 and run other applications
all coming back to issues with winhttp.dll in windows\system32
The version on this system was broken, removed by another app
everytime dotnet would install error: "winhttp.dll" is either not designed to run on windows
This was resolved by removing update https://support.microsoft.com/en-au/kb/3140245 the system then rolled back to the old version of winhttp.dll