Hello there! I'm Eurocar ! I will try to assist you as much as I can.
first thing to check if the battery cables make sure that they are tight.
second I need you to inspect the fuse box on top of the battery flip the lid and see if there is any melt down on this picture
especially check the red wire from the box to the battery cable make sure that is tight
please let me know
I did follow your sugestion and found ground cable to be slighty loose--had it tightend up and will wait to see if the problem is cured--would this also explain the flash of the dash lights?? we shall see-Kathy