Validation ($SCHEMA$): Element 'html' is not supported (VS 2015 Community or Express)

Hi
I have new web application project with WebForm1.aspx (default generated by VS).

In WebForm1.aspx every html element has the green squiggly  warning line.
Hover over the line and intellisense pops up with:

Validation ($SCHEMA$): Element 'html' is not supported

You can replace 'html' with 'head' or 'body' or 'form'; they all have the warnings.

I have tried reinstalling VS Community 2015, but no luck.
I installed VS Express 2015 but no luck.
I followed one suggestion of deleting everything in C:\Users\<mypc>\AppData\Roaming\Microsoft\VisualStudio\14.0\ReflectedSchemas but no luck.
This problem started when I reinstalled Win7 because Win 10 auto install totally messed up my pc.
I never had this warning issue before.