Having a criminal record is probably the biggest obstacle to obtaining employment. A record of just an arrest (even if the charges were ultimately dismissed) will cause a prospective employer to look to the next candidate who has no arrest record.
The only way to avoid this from happening to you is to obtain an expungement BEFORE you make your next job application. When you fill out eh "Request of Criminal Background Check," the results will be "No Record Found" if you successfully obtain an expungement of those records. You can even answer under oath that you have "No Criminal Record of Arrests or Convictions."