Guys ,i want to report that when i reinstalled the latest driver from hp website the problem persisted.
But after all i tried a same hd audio driver that i got in the software backup of my hp laptop that hp already saved in my system when i bought it.
when i installed that driver that was given in drivers backup believe me the problem is gone.
The change that i noted is that in Startup services (by msconfig.exe) a new option Realtek HD audio manager appeared that is checked to startup at system startup so in this way audio service functions good and problem is gone.
That option didn't appeared when i installed the latest driver from the hp website.
So Really Thank you everyone who has helped me.
Thank You.