Is the on-board sound device able to be turned off in the bios? Could that be the reason why the device is absent?
Can you try a complete shutdown, power off and reboot?
What system specs should I write down?
Give us some idea about the computer you have.
Eg
IBM Laptop / Dell Desktop
Pentium 4 cpu
512mb ram
80gb harddrive
What version of pclinux you are using.