SOUND CARD WARNING
Sound cards generate the most questions in the list. It is a poorly understood area of linux amongst new users. Mostly windows fudges the problems whereas linux will not do so, it has to be right or it will not work. Make sure that you understand the ISAPNP write up if your card is not a pci card. The default installation does not configure all sound cards, and some of the newer cards do not have drivers available. This is a problem that the manufacturers have failed to address and is not the fault of linux, linux catches up as soon as they have information from the manufacturers.
So your sound card does not work after installation. If you are using anything less than Caldera 2.3 I would suggest that you upgrade asap. You can fix some cards with a kernel recompile, see this site under recompiles, but you HAVE to know what sound card and revision you posess, look under windows. There is another route you can take and that is to recompile the kernel without ANY SOUND at all configured in and then use OSS.
There is another but here, OSS make download files to suit the kernel version and also the CPU type selected in the compilation. Be aware that the default kernel is compiled as SMP (Symetric Multiple Processors)