In Voyager's "The Thaw," Kim, Torres, and others are held hostage by a virtual reality "clown." The original hostages were to be in stasis for a set period, in which time "The Clown" manifested itself, resulting from the fears and brain patterns of those in stasis.
When Moriarty became self-aware, due to Geordi's error, it seems that the Enterprise considered him to be a legitimate life form, even though he was still just a hologram ("Ship in a Bottle").
On the other hand, the EMH from Voyager never was considered a genuine life form. The Clown was not alive, per se, but neither was Moriarty.