Hello Denise. I have recently had this problem on both my Plextalk Pocket units, but I have had them for the best part of ten years. At the moment, one of my units will charge up, but if I try to use it on the mains it will shut down. If I fully charge it, and use it on battery, it seems to behave. At the height of the trouble I bought a new battery for each unit, but have been carrying out tests with the old batteries. A couple of days ago I put a new battery in one of the machines, and it appears to have sorted itself out. Batteries can sometimes have a disappointingly short life, and it may well be that you have got one of those. Best wishes, Peter