Iphone 4S screen completely stopped working out of no where?

My screen has turned completely white with colored lines in it out of no where, literally. I was using my phone, and I put it down on my bed to go downstairs and get my charger and when I came back up to plug it in the screen was completely black so I assumed it died and plugged it in, then when the screen came on it was completely white and I could not do anything with it, I can hold the home and lock buttons down and that turns it off/resets it but when I turn it back on the screen is still the same. When its on I can pull up the Siri but it wont respond to any commands, and use the volume buttons and the silent button but nothing I do will make the screen come back. About four months ago I dropped the phone and the screen cracked and was completely destroyed the display thing wasn't working and apple wouldn't do anything about it because the screen was cracked and the warranty was voided so I went to a place and they replaced the screen for me and I haven't had any problems with it at all until right now and this is completely out of no where because I know for a fact that I didn't drop it or do anything bad to it in the last four days. Is there anything any one knows that could help me fix it or anything. I'm so mad because this is really completely out of no where.

Added (1). Apple didn't fix it because the crack in my screen voided the warranty so they wouldn't have fixed it no matter what the problem was with the phone. I had gone to a place in the mall that is not affiliated with apple at all that replaced the screen for me.

Well since Apple repaired it they might have missed something. The LCD may have been fine then but everyday use that can stop working. The drop does have an effect unless it has overheated or you have a bad battery which is not the case. So I would demand Apple to fix it.