Camera Turns Off Automatically But Stays On On Zooming

NOTE : THIS QUESTION IS ABOUT CYBERSHOT DSC-S730

I Use Li-ion Batteries But When I Turn On Camera It Shows Some Purple Lines (Like A Glitch , Maybe CCD Issue) And When On Playback It Shows Same Photos With Purple Lines. However, It Turns Off Just After 15-20 Seconds When On Zero Zoom……………..As Soon As I Zoom It A Little It Stays On……………ANY EXPERT GUIDE ME