have you actually gone through and reinstalled the drivers as was mentioned earlier in this thread? if not, you really really should try just re-installing it. mind you, once you've reinstalled it, DON'T DO ANY TWEAKS that would be found in mr. radar's guide... just see if it works. if it still doesn't work, and you did a clean reinstall, then it's either a hardware malfunction or there's some other conflict with your hardware (try re-seating the card in a different PCI slot perhaps). assuming you reinstall it and everything works well (wouldn't that be nice?) you could go through and apply each "tweak" one at a time to see if any of them cause problems, or to see if you like how they sound.
just some basic troubleshooting suggestions.
p.s. don't worry about pci latency or anything, assuming your pc isn't overclocked you shouldn't have to worry about it anyways... however, if your pc IS overclocked (even a little bit) try resetting it to default specs and see if that clears up the problem.