From another help site:
" reset it : hold the 'start' button until all lights display, then press 'start' again. hold the 'start' and 'on/off' button together until it reads d-end or d-off. it doesnt always work 1st time so keep trying, good luck"
Not tried with mine as mine has not failed (yet)
Wudz
Wudz, March 2008