Rule number one for laptops.
Laptop+Linux+No Sound=ACPI
You'll have to get a fresh copy of the latest kernel from kernel.org, apply the ACPI patches available in sourceforge file repositories. Then configure and recompile the kernel with all ACPI settings and DELL and TOSHIBA laptop support enabled.
This should make the sound work.
If you dont want to do this. Buy, or do an Network install of Suse 8.2, ACPI is enabled by default in Suse, making it much more suitable for laptops.