This soudns like a common CCD problem that many camera manufacturers are running into for the last few years. You may want to check with Vivitar to see if there's a service advisory or product recall for a defective CCD. If there is, they will repair/replace it for free.
Absent that, First thing I would do is reset the camera. This is a fairly easy procedure which involves either going into your setup menu and choosing "reset," holding down the menu key for 5 seconds, or, removing the batteries for a few minutes. It may be that the firmware loading got corrupted and the camera just needs to be "rebooted," which is something that turning it on/off won't accomplish. But after which, you should have the camera reset to factory default settings.
Another tip is to look for firmware updates. Download and install them.
JD
Digital-Camera HQ