Can anything be done to a car parked more than 7 days in same spot?

Maybe, maybe not, unless it's been stolen. If you don't know who owns it you can report it to the police. They remove "abandoned vehicles." The rules vary by city. In Seattle or San Diego, for example, no vehicle may be parked continuously at one location on any public roadway for more than 72 hours. It other cities the limit is 7 days. In others it's 24 hours. In many cities there's no limit.