Re: Sound Problem
According to the specs at gigabyte's website ... your motherboard audio is RealTek and offers the feature "High Definiton Audio". It's been my experience, that with that feature I've had to go to the actual audio driver website ... in your case, RealTek.com, and download the latest Vista compatible drivers.
I'd still check gigabyte's site for a BIOS update. While installing Vista SP1 is important ... it's not going to solve your driver conflict problem.