DOS Command To Delete Those Files Having Attribute Other than A

If you want to delete the files that have their Attribute value equal to "-A"(Other than A), Use the following Command:

DEL /Q /A:-A *.*

Where:

/A is a switch that selects files to delete based on attributes

-A means that only those files that have attribute value other than A

/Q is a switch for Quiet mode, do not ask if ok to delete on global wildcard

and

*.* means all files.

For further details you can visit the following reference page.
http://www.computerhope.com/delhlp.htm