My Vivitar Vivicam 5399 is refusing to turn on. It has worked perfectly up until a couple of weeks ago, when it started to turn off at random moments, usually soon after I had turned it on. Now, it doesn't turn on at all. The batteries are brand new, and I have tried putting them in different ways round. I need it for a competition in two days time, can you help me?

Have you tried to see if the battery door is completely shut? This is usually the problem with many digital cameras with batteries. Clean the battery door and where the battery touches the metal of the door. Check to see if the door is completely flush with the camera body when you close it. I know for a fact that Vivitar cameras **** the juice out of batteries fairly quickly also. If you have the USB-cord provided with the camera, plug it into your computer and see if that holds a charge to your camera. If all else fails, call up Vivitar for further inquiry, your battery may be dead.
Good luck!