Determine when and, if possible, why the trademark stopped being used. Federal law considers a trademark abandoned when it is ceased being used with the intention not to use it again. Regardless of intent, federal law also considers three years of disuse to be prima facie evidence of abandonment.
Check the status of any registration or application to register the trademark using the database of trademark information maintained by the U.S. Patent and Trademark Office. The database includes information on federally registered trademarks or applications for trademarks that are active and abandoned -- typically marked as "dead." A search for the trademark can be performed online using the USPTO's Trademark Electronic Search System or with assistance from an online legal provider.
Check the status of any registration or application to register the trademark using the databases maintained by any state where the trademark may have been used. Each state has its own trademark registration laws and typically requires registration applications to be submitted to the secretary of state or other state agency.
Begin using the trademark on your products or services to create trademark rights from using the trademark. Although you are not required to register the trademark to create trademark rights, registering the trademark with the USPTO and with any state where you are doing business will give your trademark rights greater protection against anyone who contests your right to exclusively use the trademark.