If I use attrib *.*, I see the attrib -N.
But the main problem is the -N change all files to "only read", and are impossible to work with that files.
Several time ago, some friends mention that are very difficult to kill the -N.
I suppose that are not virus, I used three anti-virus and the problem remains.
And are not a specific program, running several programs I have the same problem.
And as you realize, this block to running any program, because I need to read and write all files.