I just wanted to share my recent experience for anyone who may be having the same problem. I found online help across the internet to be less helpful. I thought this could help a VDL user that finds themselves in the same bind.

I recently purchased a new system after four years using my previous set up. In order to get the most bang for your buck, you really have to go with a 64 bit processor and operating system these days. My new system is as follows:

Dell Studio 540
Intel Core 2 Quad Q8200 @ 2.33 Ghz
8 GB RAM
Windows Vista 64 SP1
M-Audio Audiophile 2496
Dell Wireless 1505 Draft 802.11n WLAN Mini-Card (this is important to know)
Finale 2009
VDL 2.5

I got the system out of the box like a kid on Christmas morning and starting setting it up. Once everything was up and running I installed Finale, VDL and started to get to work. However, the onboard audio was sputtering, popping and filled with erratic distortion. It was not a matter of the system being overloaded or the 64 bit operating system. This distortion was random and seemed to occur in relation to video or internet activity. I powered down and installed my M-Audio sound card figuring the onboard audio that came with the Dell was junk. I booted back up and found the same problem. After much research and trial and error, I discovered that both sound controllers (M-Audio & Onboard Dell Realtek) were sharing the same IRQ with my Dell Wireless 1505 Draft 802.11n WLAN Mini-Card .

To fix the problem, you have to disable the wireless card in Device Manager and test your audio again. For myself, this fixed the entire problem. I now have crystal clear audio. In order to get your wireless card working again, you will need to reassign it to a different IRQ in the BIOS or by changing what slot is it in on the motherboard. Or, you could just get a USB wireless adaptor or run your connection through the Ethernet.
I read up on the subject and apparently this happens also with video cards and some other devices. I hope this information helps someone in the future. I was devastated for about 48 hours to listen to worse audio after upgrading to this awesome machine. But, all better now.
Good luck and  best wishes!

Luke

Thanks for posting this tip Luke!! I haven't tried it, but it sounds like a great discovery that wouldn't have been immediately obvious. I'm sure this one will come in handy for other folks with a similar setup to what you're using. Good stuff!

Normally you would uninstall the drivers for the old audio hardware, reboot, then go into the BIOS and disable the onboard audio card.  That will free up the IRQ for another device.

hello Luke if you are still there.  Sounds like i have that exact same problem.. I have a new Dell also. Can you walk me through in more detail how to change those settings in devise manager..
Thanks