Power BU Desktop fails to launch in Windows 10

[SteveD]

I've updated both my Windows 7 and Windows 10 machines with the 28 April update. WIndows 7 based machine works fine but the Windows 10 machine fails to launch. When the problem first started a standard windows close program message would display now all there is a split second display of the Power BI splash screen and then nothing.

I suppose it's not Power BI becasue it's working fine in Windows 7 but i don't know what's changed on the Windows 10 machine from last week when I was using Power BI desktop extensively.

Any suggestions would be appreciated.

[SteveD]

a re-install of .net doesn't appear to be the solution either.