When I start the computer, the speakers work fine. Then if I plug in headphones, they turn off as they should. But when the headphones are unplugged, the speakers won't come back on. I've run through the troubleshooters and nothing works.

The only fix is to reboot the computer without any headphones in, and the speakers come back on.

Sound card driver: realtek HD

Have you always had this problem or did it just start to happen? where there any changes made to your computer before this problem started to happen ( downloaded software, driver update, installed new audio card....etc.)