Okay , Yesterday I Unlocked A Blackberry Curve 8900 For T-Mobile but its orignally an AT&T phone and everything work except for When I Call People It Makes A Skipping Noise and I Cant Hear Anything. Another problem is that Im Trying to Download the Blackberry App World and when i try to download it , it says "The BlackBerry USB Driver is not installed. Please install the correct USB driver to download the application" but my phone is plugged in to the computer . Can someone help me PLEASE !