I have had EXACTLY the same experience as the poster above.
I have a 3 user NOD32 licence. I updated my 3 computers today from version 9.0.386 to version 9.0.396, and ON ALL 3 COMPUTERS it now says that I do not have an antivirus program installed.
As the poster above said, the update to version 9.0.396 is FLAWED and needs to be fixed.