Random shut down but already replaced battery. Shows "dead" android?!

Hi. Am trying to find out what is going on with a Samsung Galaxy Tab 4 10. It has recently stopped holding a charge, and started shutting off randomly. Following information here, I have replaced the battery, but now it only shows the grey battery indicator, and blinks that screen on and off continuously every few seconds. When I try to do a recovery boot, it shows the power up screen with "recovery boot" in the corner, shows the android screen, then shows a "dead" android (laying on his back with a red x), then shows a screen with multicolored text. Those all blink much too fast to read, and then it goes right back to the grey battery, blinking on and off. Any ideas? I would be grateful for any help! Thanks!