I had the same problem , and I fixed it by using the win xp disk and using the repair option.
I too have this issue!! No luck with repair option. No luck with sfc. No luck calling creative. No luck yet with MS support.
My mixer just disappeared one morning with no sound on bootup, after years of working fine. I had two sound cards that worked before for years, then nothing. I've bought
two more brand new cards of different manufacturers,
but no luck getting them to work.
Only, I've tried installing 3 sound cards with their
install cd. I've repaired xp pro. I've installed SP2.
I've searched the web for a solution. I've called
creative, and was told it is a Microsoft problem.
I've changed motherboards, too as a precaution.---No
luck. Still no sound, no mixer device, no irq
conflicts, no sign that the devices are not working in
device manager. Latest drivers, something is wrong in
the OS that windows repair doesn't fix. Unstalling/reinstalling drivers doesn't fix.
This seems to be a not so rare xp issue. XP pro here.
It may be a reg, sys file, or surround sound issue. Just reformatting and reinstalling windows is a bit like bulldozing/rebuilding a house to fix a roof leak that a good roofer could fix in 15 minutes. It shows a weakness in the knowledgebase, or framework that everything is hanged upon. Mostly, constant wiping and reinstalling is just a stupid hackshop (ala bestbuy) answer for everything, because of laziness or economic pressure not to spend time understanding the problem.
Unsolved 
