Can a woman get pregnant before she begins ovulating and is there less of a chance?

The only time a woman can get pregnant is when she ovulates. The egg can be fertilised for about 36 hours. However sperm has been known to live in the vaginal tract/womb/fallopian tubes for up to 5 days, so while a woman can only get pregnant when she ovulates ie when an egg is available for the sperm to fertilise, the length of time that sperm can live for must also be considered when timing intercourse.