You need to tell us what your hardware is first (as per the other thread you started a few hours ago) then we can give you some advice about what you want to try and where to go from there. Its worth reading the kernel howto as you'll more than likely end up wanting to/needing to recompile your kernel. When you installed Slackware what Kernel did you install?
The kernel howto is at
http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html
cheers
Jamie