sharp LC-32P50E, how to set auto input selection?

Probably the title is a bit vague there, but when I want to watch a dvd, I have to manually set the screen to the required input myself, otherwise I the screen shows the tv programme I as watching with the dvd sound playing in the background. Does anyone here know, in simple terms, how to set the screen up to auto switch to the dvd input when the dvd player starts to run?
Thanks.

Edit: This should be in the LCD forum, not here, would appreciate a mod moving it if pos.

[neilmcl]

How is your DVD player connected. Only scart connections offer automatic input switching!

Ah right, its connected via component. I won't have the auto facility then, thanks.