There are a few things that may be wrong with your device.
1.) The LCD screen may no longer be connected properly. To check if it is go to the following page. [[Sony Cybershot DSC W730 Troubleshooting|Troubleshooting]]
2.) The power may be off to turn on hold the power button on for three seconds.
3.) The LCD screen may have broke. To replace go to the following site. [[Sony Cybershot DSC W730 Troubleshooting|Troubleshooting]]