After sitting for seven years, looks like you're going to need a new battery. Make sure you charge it at a low rate, overnight, before you use it. Don't use a car battery charger or you'll fry the battery. A battery tender is a good buy with the battery, as it'll charge at the correct rate, and won't let the battery overcharge. ( even if the salesman says you don't need to charge it - charge it - we've learnt from experience that if you don't, then you'll be buying a new battery very shortly)
Also, the carb is the Achilles heel of the GZ, so make sure you add a carb cleaner to the first tankful of petrol, then every 3 or 4 fillups.
Also, you may need to buy an aerosol of contact cleaner, and blast it into the safety switches, i.e. red switch, starter button, clutch switch, and sidestand switch.
