This happened to one of my cousins. He is a Droid lover (but I like Atrix a lot) and got a problem with his Screen. He wanted to repair and and I said I can do it. I just said (I really didn't know how to do it). I'm his hero and didn't want to make him sad. So I was searching a way to do it. I went to few places to do it but they said that it will risky and the cost also bit high. Then I thought to do it by myself. Phone was working fine but sometimes gets issues with the touch. So I found some articles about repairing the screen. I saw a great article and could repair it at home. But I had to buy some tools, it is ok now I know how to repair phones similar to Droid 4. But when you do it you should be very careful since the touch screen panel is very sensitive. Thank you Motoask for the guide (I can't remember the author's name).
One more thing, you should make sure that you have all required tools before starting this process. Otherwise you will be in a big trouble