m250 power failure

I have an m250 2G purchased in june 2007 as a xmas gift so not used till jan 2008, and sparingly at that. All of a sudden the unit powers up for 1 minute and then shuts off, like a low battery. The battery icon shows full charge and I have verified by 2 new fresh batteries that battery power is good. Anyone have any experience with the m250 2G power failure as to switch or battery contacts? The product appears to have been discontinued even though tech support told me in Dec 2007 there were no plans to discontinue. It will annoy me greatly to pay postage to return for a refurbished model that may be bad as well.