Audio drivers

just install the audio drivers correctly and then go to contol panel and look for sounds and audio devices , open that and configure correctly .. and also check this ... go to start/run and type msconfig ..in that go to startup tab , there u select he option enable all , then apply and restart your computer...your problem will be solved....

If it's an Intel board then you can get them here:

http://downloadcenter.intel.com/default.aspx

But just because it has an Intel 945 chipset doesn't mean the actual board itself is intel... it could be another sound card / chipset on the board. Make sure you check what brand the actual board is. 945 is the chipset...