After much work, I finally got sound working on my system. I installed ALSA and set that up by running alsaconf. It found my sound card (Ensoniq1370), and it seemed to work fine (every program could play sound normally). (am running Debian if that helps).

However, I just rebooted and now sound isn't working again in most programs. It's still loading the drivers and such. If I open "Volume Control" it shows 2 cards:
Dummy [Alsa Mixer] on the left
Ensoniq AudioPCI [Alsa Mixer] on the right.

I can't remember where I saw it, but I believe I saw that it had mapped the dummy sound to /dev/dsp0 and the real sound card to /dev/dsp1. Also if I open something like xmss and go into the preferances.. by default it seems to be playing through dummy, but if I change it to the real sound card in that it plays normally.

So I think my problem is that somehow I need to get /dev/dsp0 and /dev/dsp1 swapped... or maybee remove the dummy one altogether. Running kernel 2.4.27 also.

Any ideas?

First of all, there is no /dev/dsp* in alsa. If you have some /dev/dsp* files, it is OSS emulation in alsa.
The dummy one might be something for testing purposes. Can you try running lsmod and check for some modules with 'dummy' in their names? If you find some, remove them (rmmod) and remove them from your start-up scripts (/etc/modules in debian, don't know about others).

rmmod said the device was busy, so I changed /etc/modules (commented out the line: snd-dummy) and rebooted.

That seems to have done the trick, thanks!