A city fire inspector says it was an overheated laptop that was the cause of a house fire on Ryerson Crescent last week. No one was injured but the damage is estimated in the hundreds of thousands of dollars. Eric Nordlund says it appears that someone left the portable computer on a couch where air circulation was a problem. Meantime, Nordlund says it's important to keep fire alarms working in your home. He points to two apartment fires from last week, on Archibald and Simpson Streets, where it was noticed that fire alarms in the dwellings were disabled. In both cases he says careless smoking was the cause of the fires.