My battery was low one day (20%), so I plugged it into my computer. 20 minutes later when I checked up on it it was completely dead. As I go to turn it on it will only bring up the red battery symbol and lightning bolt. Hard reset and it is back to the same symbol, only 5 minutes later a double, blurred apple symbol appears (two overlapping apple symbols). It continues to sit like this and sometimes after will go to a strange orange/red/pink/yellow screen. My question is would replacing the battery completely more than likely fix it? I took it to apple store and when they tried hard resetting it nothing happened so I just got an iPhone 4s. When I went home ad tried it again out of curiosity it did what I saw it do earlier. Please, any advice on whether or not it is just probably a defective battery or what else could be defective?