Few things to try:

Lower your volume in the Windows volume control.

Lower the bass/treble settings in the Advanced part of the volume control.

Reason being, if your audio volume is multiplied by the Windows volume and multiplied at specific frequencies for the bass and treble boost, the audio can be distorted sufficiently for glitches to be introduced into the output.  These glitches therefore sound like snaps or pops.  It's also possible for the software to introduce these glitches by not mixing the source sounds properly, or mixing too many sounds at once.

It's an APCI system.... IRQ's are irrelevant.

This is a 2 year old system...if the sound problem just started, it has nothing to do with the bios.
 
I gave the link to the correct Realtek drivers in #10....I have no idea why you went on a search and destroy mission for the wrong drivers (not that I think it matters as it pertains to your problem).

Getting rid of the 190.38 drivers is a plus for anyone's system, but it runs off the Northbridge, so I never thought  that it was the cause and cure (other than you said it started after their installation).My bigger concern was that 300w PSU you undoubtedly have.That alone could be the 'bacio della morte'.

The PCI card you ordered will be running off the same bridge as the HD chip (as well as LAN, USB and ATA...the 'problem' could be in any of them). Unless the Realtek chip is defective, your chances of encountering the same problem are relatively good. The chances of a defective Realtek chip are close to non-existent. The chances of an under-powered system are as close to obvious as one can get.

That said, my original thoughts were that it was a 'simple' setting (thus my #1 post). At this point, a more likely scenario is electrical interference via the boards VRM's in response to the new card's power pull. The bad news is there's not much you can do about it with the present setup. The good news is the PCI card will likely work..... if it doesn't suck the life out of your PSU.....

....hang on to the receipt.

LOL... sorry about the missing info yrag,   I put in a 500 watt PSU before the card. Its a Dell Compatible PC Power and Cooling "Silencer" and it went in without any problems. It was working great for like a week and I didnt notice any sound glitches until I put in the 9800GT. The original 300w PSU from China didnt even have a pcie connector for the 9800GT... so it would have been more than just a power issue. I looked at that link you left me for the realtek drivers and i couldnt get in there... let me check again. I could always uninstall this driver and put in that one in. Thanks a lot for all the suggestions and help.

ok I got in there... it was just a little bit of confusion. I'm thinking I should probably freshly install Win 7 after all this in and out driver business. Win 7 is able to take a pretty good beating but it would probably be better if I started from a fresh install with all the right drivers.

If you just installed Win7, than yes, a re-install would be a good idea. Short of using a driver cleaner in safe mode, Nvidia and Realtek will leave 'stuff' behind. One being those Stereoscopic drivers.

The  PSU you have is excellent. Keep in mind that the VRM's could still be the problem (OS re-install or not) and as already stated, there's not much you can do about it. Since the PSU is no longer an issue, the PCI card should work fine.
 
If the Realtek chip 'sound' is more of a crackle then an actual stutter (noise vs. action) then you can cut down the board EMF by 'Enable Spread Spectrum' in the bios.

Other than that, Tuesday isn't that far away............

I ran a fresh install of Win 7 with those 186.18 and R230 drivers and so far so good. If theres any popping or crackling I have yet to hear it. Ive listened to lots of different stuff... Smashing Pumpkins, the Eagles, Dire Straits, Squeeze, REM, Annie Lennox, and even Franz Schubert, and no noises. The more I listen, the more I'd have to say this computer has never sounded better. It must have been that 190.62 driver causing all the rukus after all. That R230 driver really boosted the sound quality too.  Hooray! I'm listening to Jeff Beck - Wired and it sounds really crisp.  Thanks a lot for the help Yrag.

Wow, fancy telling me how to do that?

follow yrag's instructions in reply # 10

I actually had to start in safemode to uninstall them and use driver cleaner pro to get rid of all traces.

Then I installed 186.18. Systems fine now.

Lol, just reading back over this thread, and noticed this gem. I was actually playing with the meaning of the sentence and pointing out it really read

'I was getting BSODs but then I uninstalled them' with the them refering to the BSOD's rather than the Drivers.