“My zucchini has had many flowers, but no fruit...I have two baby yellow bell peppers, lots of flowers on the green pepper with no fruit.”
Do you have bees visiting your zucchini? Zucchini are insect-pollinated, since they have separate male and female flowers. If you don’t have bees, you can hand pollinate them by clipping a male flower, carefully pulling away the petals to leave the stamen exposed, and then “painting” the pollen inside the female flowers. You need to do this early in the morning while the flowers are open.
With the peppers the problem could be temperature, since some peppers don’t set as well when it’s really hot. Also, have the winds been calm? Peppers and tomatoes are self-pollinating, but need a little wind to shake the pollen from the male part of the flower to the female part. If the wind is not doing the trick, you can try hand-pollinating your peppers by vibrating the flowers with an electric toothbrush or electric shaver.
There are lots of videos on YouTube showing how to hand pollinate - just search for squash pollination or pepper pollination. Good luck!