Loses CDROM after sound is installed

Now he has 600 mhz AMD with ATX case and a 10 Gig hd. The grief comes from the m/b. It has onboard sound. When we try to install what appear to be the drivers we loose the CD-ROM, so badly that windows does not recognize that it is there even with a search for new hardware.

Mainboard: Microstar Inc KT-7 Pro 6330