Hi Chris. Just heard back from O Support re: how to reset the C-990 to its default settings. They say to "please remove the batteries for more than 24 hours." Go ahead and give that a whirl. I'll keep my fingers crossed for good luck.

If the problem continues after resetting the camera, then it may be a mechanical issue. That would be a bummer! I'd suggest you contact Olympus Support and see what they say. The UK site lists the C-990 in their "archived product" list. Here's their web address for support ...
http://www.olympus.co.uk/consumer/208_1636.htm(By the way, digital cameras have come a long way in the past 5 years. If yours requires a repair, and the cost is high, you might be better off to buy a new camera.)