Antivirus software is only as good as its last update. A valid key ensures you have the latest virus definitions.
Appendix A: Example activation sequence (online) shield antivirus product key
Let me know the exact message you're seeing, and I can help you troubleshoot it. Shield Antivirus Support | ShieldApps Antivirus software is only as good as its last update
As requested, we are resending your Shield Antivirus product key for your records. shield antivirus product key