Mute in-built speakers

The sound is routed to the speakers or headphones by a small switch in the headphones jack - in your case that switch has failed. You will have to open the laptop and replace the entire jack so take it to a repair shop, this is a delicate job, leave it to the experienced ones.

You Have To Hook Up A Mic Cable From The Rear Of The Monitor To The Modem.

You may have to download a different audio driver for your Vista OS.

Asalam u alikum,
Dear friend yours broblem have been solved if you do this steps.
1. first go to the start menu.
2. then select a control panel.
3. In control panel select option (sound,speech,audio devices) then select change the speaker setting, the sound and audio properties is opened, go to the speaker setting select advanced option in advanced option change the speaker setup and select stereo headphone and apply it.
I hope its solved yours problem.
Thanks

good day

have you tried inserting the microphone plug to the red/pink socket in your sound card?

my presario c700 has a built in mic try just connecting headphones in and using the built i mic

I have compaq presario c773tu laptop .I can not find sound driver on internet.

USE THIS LINK AND YOU SURELY GET DRIVERS FOR ALL WINDOWS XP VERSION DRIVERS FOR C773TU. I AM TESTED ON MY COMPAQ PRESARIO LAPTOP WORKING SUCCESFULLY.
DOWNLOAD IN CORRECT ORDER.

http://saysprasad.wordpress.com/2008/08/08/compaq-presario-c773tu-laptop-drivers-for-windows-xp/

Bottom of right screen right click on volume icon. Highlight adjust audio advance. Click on speaker set up, scroll to headphones and then click apply. Now when you plug in your headphones they automatically cancels the speakers.

Have you tried a pair of known working headphones?  Does the motherboard have built in audio?  Make sure nothing is muted in the advanced audio menu.  Make sure you're connected to the right connector. (usually green) And most audio cards will come with drivers if they need them, but you can try these downloads from the realtek website.

http://www.realtek.com.tw/downloads/