First thing I always ask about crackling audio is does the same crackling and popping happen when you listen to cd audio or mp3 from a physical cd or dvd drive? Could be your SATA driver
working inefficiently if so.
There are so many potential causes for this. First thing to check is audio driver. If latest, try older. If older, try latest.
Visit your motherboard manufacturer's site or Gateway and update the drivers
for everything they offer for Win 7.
Your lan driver could be in conflict with your audio driver. Does it only happen when packets are being sent and/or received?
Defragment your hard drive(s).
Go into your bios and disable every port not in use, like serial and/or parallel. Disable the floppy drive too, unless you actually use the thing. Windows will boot faster.
If you have a firewire (IEEE 1394) adapter in use or not in use, change it to a generic driver. Sometimes in these cases, there's success in untying certain services to each other in the registry and then disabling one. I'll tell about that later too if it gets to that.
I see you have an old video card. The driver you're using for that could be not so great causing interference in your pc operating well.
I've also fixed machines with this problem by going into bios and generally making sure things are correct. Machines with hard drive or controller misconfigurations or that haven't been optimized (i.e. set wrong) can exhibit this behavior.
You may have some luck by changing the latency for the audio using the PCI Latency tool from Guru3d.com, although this is a long shot. http://downloads.guru3d.com/download...t=951#download
I'll think of other causes for ya if nothing I've said already has helped. Good luck.