Low volume from computer

[70mlbu]

I am using the onboard sound from my ASUS A7N8X Deluxe motherboard through a mixing board. The volume is very low as opposed to the JVC CDG players I used previously. When I boost the line for the music on the mixing board it becomes distorted to the point where I would not want to use it in a show. I was trying to get Hoster ready for a couple Christmas parties coming up but it looks like I'll be using the trusty old CDG players until I get this figured out. Any suggestions? I have an old Soundblaster sound card in an old computer I could use but I thought the ASUS onboard sound was supposed to be a good sound controller.

Thanks for any help/suggestions.