The Frederick County Virginia records are currently accessible through FamilySearch.org. Once in their site, after creating a username and password, click on 'Catalog' found in the drop down menu under 'Research'. Then place United States, Virginia, Frederick County in the search bar, It will open to give you many options. I prefer the 'Minute and Order Records' listed under 'Court Documents'. These records follow the month to month County occurrences. Sometimes, an index to these records will be found at the beginning or end of each book, but for the most comprehensive research, read slowly page by page. Another informative option available under Frederick County on Family Search is to research the land records, deeds, and indexes.
Hope this helps!