No Audio Device Installed

Hello,
I'm having a problem with my audio. Right now it states that i have no audio device installed however when I go to my device manager, it states that all the drivers and codecs are installed properly. The only way I have been able to get sound started on my computer was to go to services, click on Windows audio and start it. However, that is only a small work around and doesn't completely solve the problem since I have to do it every time I start my computer. My audio driver is a SigmaTel High Definition Audio Codec. I don't know what is going on or how I can fix it. I have Windows XP sp3.

When i click on sound/video controllers on my device manager, I get the following list (for sound):
Audio Codecs
Legacy Audio Drivers
SigmaTel High Definition Audio CODEC

Any help would be greatly appreciated.