change video aspect ratio
 

My computer monitor and my tv screen have 16:9 aspect ratios. I have my computer set up to alter displays to my tv so I can watch videos on it. The problem is I have a video that is in a 4:3 ratio, giving me block bars on the left and right side of the screen. I have a plasma tv so the black bars can cause burn ins. What I want to do is have winamp stretch the video out to a 16:9 ratio. So i went into the preferences and clicked on lock my ratio, and set my ratio to 16:9. but the black bars on the left and right still show up.

anyone know what I should do about this?