HI SUVGA,
Welcome to the HP forum!
Thank you for your post, I will do my best for your.
I understand that you have no sound and the" No speakers or headphones plugged in, Audio codec 52 error". Hear is a link to Troubleshooting Sound Problems with External Speakers and Headsets in Windows 7 and No Sound from the Speakers (Windows 7) . You can run the HP Support Assistant to aid in updating drivers and resolving issues. You can also try running MS Fix It to help troubleshoot. Please let me know the outcome.