Hibem1971,
Welcome to the HP Forums!
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Thank you for your query, I will do my best to aid in this endeavor.
i understand you had an issue, which AVG resolved, but you no longer have sound. You can use the HP Support Assistant to help resolves error and find drivers. You can also use MS Fix It to help with this issue. Here is a document on No Sound from the Speakers (Windows 7), to guide you through some troubleshooting. You have an option to do a restore back to a known good time. Using Microsoft System Restore (Windows 7).
If you would like further assistance would you provide the exact model of CQ43 you have. How Do I Find My Model Number or Product Number?