I have gigabyte MB, realtek hd audio, win7 and had the same issues after several searches and trial and error here what I did to correct the issues.
1. turn off windows auto install drivers
http://www.sevenforums.com/tutorials/82137-drivers-turn-off-automatic- driver-installation.html
2. used CCleaner to uninstall all realtek audio drivers, and dolby EQ
3. reboot, enter bios turn off onboard sound ( azalia ) save and exit
4. used CCleaner to delete all realtek/dolby registery errors/items
5. downloaded realtek drivers 2.41 from guru.com
http://downloads.guru3d.com/Realtek-HD-Audio-2.41-Driver-download-
2462.html
6. reboot to bios. turn on audio card. save and exit.
7. install realtek 2.41 drivers.
8. enjoy my sound system with sound effects and room correction installed.