Here is my problem:

I need to install two ISA cards on my 486 (running slackware 7.1). I have never tried to install non-PnP hardware before, so I have absolutely no idea where to start.

The first card is a sound card and I think it is a Creative Sound Blaster 16. On the card, it says "Copyright Creative Technology Ltd. 1992". The chip says:

CREATIVE
(c) CREATIVE TECHN92
CT1746B-067 JAPAN
9348EDO38

THe second card is an ethernet/serial port card. On the card, it says "Intel 8/16 lan adapter". On the chip, it says:

INTEL
201969-221
uPD65046GD-189 (the u is actually supposed to be a miu)
9504KVA90

Any help would be much appreciated.

Try ALSA for your soundcard: http://www.alsa-project.org