CCleaner: Registry Entry: PN_Shield:Max ?

When I run CCleaner, often I get this entry that says "Obsolete Software Key":

PN_Shield:Max

Even when I delete the key, it usually ends up back in the Registry.
I did a G**gle search for the term, but did not turn up anything helpful.

Does anyone know what application/process is creating this key,
and maybe how to delete it permanently, so it doesn't show up again?

I play Call of Duty: Modern Warefare 2 for entertainment, but I only play the single player games.
I'll have to check and see if that entry re-appears every time I run the game. You might be right about this.

The scan says "obsolete software key", so maybe it's not required, and there's a way to stop it from showing up.