Haunted Office (2002)

Original title: Office有鬼

Employees working at a high rise building begin encountering a series of strange occurrences. Ken, a recent hire who attracts to the lovely, but spiritually harried Shan. Meanwhile, Pat is apparently terrorized by the evil demon who resides in the last stall of the woman's bathroom. And Richard, a mean boss of another company in the same building, wants to get rid of his long-time employee Mary and begins to suspect that his entire staff has become ghosts.