What exactly is ovarian failure and what are the symptoms?

Menopause. It really means that there are little or no eggs left in the ovaries and therefore the ovary is not making any more estrogen. Women stop having periods, they may be hot/sweaty during the day or night, may have vaginal dryness, decreased sex drive, and be prone to depression/anxiety/mood swings. Sometimes it happens all of the sudden and sometimes gradual.