Jane, I must admit I am not familiar with that model. However, the problem is either the fax memory or a stuck print job. What was the last thing you were trying to do, fax or print? If faxing you can try to unplug the power supply and waiting about ...
Unplugging will not work. Power off the fax while holding down the reset key (small yellow key // on top of fax.) While still holding the reset key down, restart the fax machine. You may have to do it a couple of times, but it does work. IT guy, man...