Rebecca, Do you know that your ancestor served (for either side)? if so, use the National Park Service's Soldier's and Sailor's Database (serach for it using Google). Try multiple spellings, because the search engine turned up nobody in the 7th Virginia Cavalry (for example) named "Boon" but turned up a couple named "Boone." Not sure why, since "Boon" is found within "Boone." Anyway, be creative and flexible in your spelling. Our ancestor's were, but our computers are not.
If he did not serve, then I would recommend talking with the oldest living family member you have, find out the names, places of death, birth and marriage of your grandfather, great grandfather, etc. as far back as your living relative can remember. Be careful however, sometimes old memories "misremember" things. Some stuff my mother told me about family history was flat out wrong.
Virginia passed a law in 1853 that all white births, deaths and marriages had to be registered in a book at the county courthouse. If you can get the county where your ancestor lived, you may be able to find out more about him. The marriage register listed name of bride,m name of groom, places of birth of bride and groom, parents of bride and groom, name of the minister. If you are smart about using this info, you can find out a bunch about your family tree. All of the existing books (many were burned during the Civil War) are copied on microfilm at the Library of Virginia in Richmond.
Good hunting.