Optio WP crash

Ever since I've had my Optio WP it has crashed occasionally. The screen freezes and the camara doesn't respond to any of the controls, not even the power off! I have to remove and replace the battery to reboot the camera. Is this a common fault? can I do anything about it? I had the Optio 33 WR before this one and never had a moments trouble with it. (I stupidly left it in a Taxi in Lanzarote) The crashes were only very occasional events but have become more frequent: today the WP crashed 6 times in an hour! Any ideas anyone?

I have the WPi and it only started playing up after I put it in the water, eventually the screen died, its sitting in a shoebox somewhere

Have you had yours in water : the WPi is rated for 3mtrs of water. I believe the seal may have leaked on mine.

Yes, I do sometimes take pictures underwater. I'm a marine surveyor & occasionally use the Optio to photograph areas of boats below the waterline. (I did this with the 33WR as well, although it was not rated to be as waterproof as the WP) There are no signs at all of water ingress into the WP, there don't seem to be any signs of physical damage, I'm no sort of expert at all but I wonder can it be a software problem? It reminds me of the old PC Windows crash!