I don't know what this software does, but I think it just changed /etc/mce/mce.ini. In that case, you can fix it without reflashing. It's within [PowerKey]. I believe the defaults are
PowerKeyShortAction=menu
PowerKeyLongAction=shutdown
PowerKeyDoubleAction=disabled

Be warned, if you mess this file up, you have to reflash anyway!
After the changed, you have to reload mce: /etc/init.d/mce restart

If you don't know how to change the file etc, maybe someone else can help you. I'm currently in a hurry actually :$