Re: my play store was stoped working..
A factory reset should be a last resort, John, not a first step. Spiral and Perv are on the right track.
In Settings / Application manager, scroll all the way to the right, then scroll down until you find downloads. If it is marked as disabled, tap that row, tap the enable button, exit and try the Play store again.
If it's not disabled, or you did the above and it still won't work. scroll down to Google Play store, tap that row, and tap the Clear cache button, then the Force stop button. Exit, and try the play store again. If it still doesn't work, repeat but tap Clear data, then Force stop.
If none of the above works, let us know and we'll try something else.