My sound is doing odd things?

It shuts off. I updated windows and thought that was it, but the sound didn't die right after, it took about a month or two after I updated to windows 7. I have a HP Pavilion dv9000 and I'm completely unsure as to why my sound's no working properly. One day I was watching videos on youtube and it died. I restarted, it was fine. Then it died again about halfway through a vid. I kept tryign to revive it and it just went ka-poot.

Now, a while later I run my eset smart security and the sound randomly starts working again. The scan found NO viruses, and now it died again after about a half hour, and I tried updating and everything. It just won't stay on. System restore doesn't fix it. Nothing I've done does a permanent fix.

As far as I can see I can uninstall and reinstall it every 15 minutes, including a full retsarting of my computer, but it only works for a little while.

Any suggestions? This is a very irritating problem for me ><