No Audio Output Device Installed

I'm using a Compaq Presario and my sound is gone. It says "No Audio Device Installed". I've been to the control panel and there is nothing listed for Sound... it was there... but now is gone. I tried reinstalling audio drivers and using recovery manager which did not work. I tried using Device Manager to scan for hardware updates. Nothing is working... it seems to work correctly then when my computer restarts it says that there is no device so it won't update the driver. Anyone know what else I can try for this?