So today my iPhone 4 screen just went black. If I hold down the home button the voice control comes on, but the screen is totally black. Probably a month ago my lock button became unresponsive. I can't turn off my phone, lock it, or do the reset thing by holding down the lock & home button. I don't know what to do. As we speak i am resetting it on my computer, but i don't think that would work. Also, a couple months ago I got my iPhone conversation changed to a blue iphone rather than white. I don't know if something was disturbed while it was being changed and that's why its not working! I don't have any insurance on it or anything, so taking it to AT&T or Apple would probably be a waste of time. If I can't fix it myself I'll probably buy a new one, though I don't want to. Thanks!
Added (1). Sorry, it put this question in the wrong section. :/