Battery dying

My 2007 highlander wouldn't crank. We boosted, it crank, got battery to full
power it cranked hour later seemed fine. (Mean while a red light with key inside
was blinking, kept blinking) car was dead aga in next morning, boosted took to
auto zone, they said battery good try cleaning post, we did ran car around few
hours, got up this am car completely dead as before. Red light with key in it was
still blinking when I parked it last night, does that have anything to do with it?