Converting video files from a dash?

I have a t-mobile dash and I'm trying to convert its MP4 video camera
files into something natively readable by windows XP.

It appears that the dash uses non-MP4 compliant audio codecs so it's
very difficult to find a web converter that can read it's files.
(most converters either crash or play blank/mis-timed audio).

So far the only converter that appears to work is the AVS video
converter, but it has a $29 fee when unlocked. I've had no luck with
the 10+ free converters I've tested so far. Has anyone tried and
successfully converted Dash-created MP4 files with any free
converters?

-MVL