Right now I know what you are going on about.
The Blue on/off function has nothing to do with the picture, it is a option that when there is no signal recieved on the set that a blue screen can be displayed or with the function off the screen goes into a sort of stand-by mode leaving the screen black.
Now I think what you have seen is that the picture on screen looks almost like it has a blue filter placed over it. Now this is because the colour palet is set to COOL 1 or COOL 2 in the picture settings, there is also a WARM 1 and WARM 2 which make the picture too yellow. To get rid of either of these effects simply press the MENU and select the Picture settings and on the colour options at the bottom you will see the option to change the colour palate, simply set this to NORMAL and et vola! that blue push that you are refering to will have been banished back to whence it came!