Ok, I stuffed up.

I have uninstalled something and no I have no sound.

Windows detects a PCI device when booting though it can not find a driver for it.

I have run through all the cds that came with my Dell laptop and tried to install what I could with no luck.

The Sigmatel installation stops saying "no supported device"

The only way to get sound is to boot of the diagnostic CD and run a sound check.

System:

Dell XPS M1710 

Windows XP SP2