I changed the battery in my phone, and when I turned it on, my lock screen wasn't showing! I can see the notification bar on the top with the time, and it constantly fluctuates between having signal or not having any. The rest of my screen though is just blank, and my phone keeps vibrating the way it does when one of my apps crash. I tried rebooting my phone and taking out the battery and putting it back in, but it's just not working, and i don't know what to do. I have a samsung galaxy vibrant, if it matters. i cant even get into my phone :c help!